God is Your Strength
I am so sorry to hear about your situation and your daughter's pain. I am a parent of three grown ones myself and very well know the heartache we experience for our kids, no matter what their problems are.
Let me first talk to you about you, and then about your daugher. You say "if only you could stand in the Lord." My dear, you have not yet realized, have you, that that is not your job? He keeps you, not the other way around, and He is keeping you my dear, every day and every moment, whether you know it or recognize it or feel it or not. ("He that keepeth Israel neither slumbers nor sleeps." "Faithful is He Who calls you, who will also DO IT!")
It does not depend on your "having time" with Him or your making sure you don't let other things clutter your mind. That's the way of self-effort, and since the way of self-effort always depends on what you do, and you never do enough, then that way, like the law, fails always. You "feel" spiritual and "with" the Lord when you have done those things, i.e. read your Bible, spent time in prayer, etc., and then you don't "feel" spiritual when you do not do those things. But God is more certain and faithful to let His life in you, you whom He bought with the precious price of the Blood of His Son, to let it depend on your actions and attitudes. (Oh, we have been corresponding long enough for me to know that you can find scripture quotes that seem to be the opposite of what I am saying, but hear me out!)
The law, which is what you are under when you think it depends on you, fails, and always fails, because of "the weakness of the flesh," (Rom 8:3), and it is perpetually supposed to do so, and will perpetually do so, that you might finally come to the end of this false (and idolatrous) idea or consciousness that God's life in you depends in any sense on you -- except for your reception of it! You MUST receive, but then when you HAVE received, then you transfer into faith, which is you believe that HE has done it, is doing it, and will continue to do it. What you take takes you. When you eat a sandwich, its nourishment (or lack thereof) becomes you -- it has its way in you once you have received it. You have no more power over it until it runs its course. Now you have taken the Lord of the Universe inside you, and HE makes promises which do not depend on you to fulfill, but on Him. Depend on the One Who Promised, not the one who receives the promise (you)!
Dear, I am consumed with God, and I don't give a thought to whether I spend time with Him, read my Bible, have a prayer time, etc., and I've been like this for nearly 30 years. I walk around in Him and as Him. He is my Living Truth, my every moment Wisdom, the ever present Guide, who leads me in the path of righteousness. As the Psalmist said, (2 Sam 22:33-37) "God is my strength and power: And he maketh my way perfect. He maketh my feet like hinds' feet: and setteth me upon my high places. He teacheth my hands to war; so that a bow of steel is broken by mine arms. Thou hast also given me the shield of thy salvation: and thy gentleness hath made me great. Thou hast enlarged my steps under me; so that my feet did not slip."
People read that but don't believe it applies to them. It applies to YOU, dear! Believe it! GOD IS YOUR STRENGTH! HE MAKES YOUR WAY PERFECT! If it depends on what you do, it will never be. But because it does not depend on you, but solely on Him to fulfill HIS OWN WORD, it IS TRUE IN THIS CURRENT MOMENT. This is your life the Psalmist is speaking of, dear!
Another Psalm says, "I will both lay me down, in peace, and sleep, for thou O Lord, only makest me to dwell in safety." Ps 4:8 You can live in His rest -- lay down and sleep -- because HE ONLY MAKES YOU DWELL IN SAFETY! Believe HIM! (O thou of little faith!)
Surely we do not insult the Lord by saying He does not fulfill His own word. This is the "rest" of God that it speaks of in Hebrews 4. My own testimony proves this, my dear. I am the least of men. Yet HE is mighty in me, because HE IS, and I simply dare to say it! I don't make Him mighty by my faith, but only acknowledge the Truth that He is in me.
Now my mind gets distracted just like yours. But that is as it should be. We have to have the distractions and pulls of the world, which act as a springboard for our faith to be expressed in the face of opposites.
What things soever ye desire, when ye pray, BELEIVE THAT YOU HAVE RECEIVED THEM! (Mark 11:24) HAVE received, not one day will! HAVE already! At the moment of the prayer, you have gotten your answer. It may be a while before it shows up in the flesh, but that is not our business. Our business is to thanksgiving because HE HAS DONE IT!
That's the key to this faith life, dear -- to accept God's promise in us as True now, not in some never-seen-imaginary future. Abram obeyed the Lord and changed his name to Abraham -- "father of many nations" -- when he did not yet have a true heir, and he and his wife Sarah were past the age of childbearing. That is faith -- to say it is so BEFORE the eyes see and the ears hear.
Now, dear, about your daughter. You have this faith for her. Thank God for what He has done, rather than despairing for what you do not yet see. It does not matter in the final analysis whether your daughter is ever relieved of her pain in this life, though I know it is greatly hurtful to her and to you her mother because you feel powerless to help her.
I know the same situation with my own children, especially my middle child who is 34 and has had great trouble in his life of his own making. I, too, cannot "do" anything really about his problems, and he gives me chest pains, if you must know the truth of it. But what I experience in the flesh (doubts, fears, pains, worry, frets) only give fire to my faith, which is that God HAS delivered Him into Himself and that His grace is active and alive in Him. I know my son, because of how his life has gone, now has started to experience the misery and stress of it affecting him deeply, and I see God in his pain and stress. It is God's way with Him. And I rejoice, though my heart is pierced through with an arrow.
It is the Man of Sorrows Who sorrows in Him, because I see nothing, nothing, separated from Christ, and even my son, who does not acknowledge Him, is part of "that which is behind of the sufferings of Christ," and I am seeing him redeemed and then a redeemer of others. So I thank God continually that HE HAS DONE IT, even though I can't see it, and it often looks like it is just the opposite and there isn't a chance it could ever be. But the One in me stands strong even in my weakness (i'm supposed to be weak you know -- you, too!), and in that weakness is the mighty power of the Living God.
Don't despair, dear. God means all this for good, and you can see it in your faith, even if you cannot in your flesh. Stand there, then. And know this, that even if you feel dark and don't think you can believe, HE does anyway, because He cannot deny His own work. Believe HE HAS FULFILLED your requests for your daughter, and then rejoice, in tears if necessary, in thanksgiving, that HE HAS DONE IT. Because I tell you HE HAS!