Paul Miller gave a fantastic message at the 2011 Desiring God Conference for Pastors: Helping Your People Discover the Praying Life.
He understands what it is like to love a child with a disability.
He was invited to speak because he wrote a great book on prayer, A Praying Life.
It is full of reminders and pleas like this:
Prayer is asking God to incarnate, to get dirty in your life. Yes, the eternal God scrubs floors. For sure we know he washes feet. So take Jesus at his word. Ask him. Tell him what you want. Get dirty. Write out your prayer requests; don’t mindlessly drift through life on the American narcotic of busyness. If you try to seize the day, the day will eventually break you. Seize the corner of his garment and don’t let go until he blesses you. He will reshape the day.
Paul Miller, A Praying Life: Connecting with God in a Distracting World, Kindle Locations 2959-2962
We can absolutely trust him! God even has it covered when we don’t know how to pray, or simply can’t pray, because our sorrows are too deep:
Likewise the Spirit helps us in our weakness. For we do not know what to pray for as we ought, but the Spirit himself intercedes for us with groanings too deep for words. And he who searches hearts knows what is the mind of the Spirit, because the Spirit intercedes for the saints according to the will of God. And we know that for those who love God all things work together for good, for those who are called according to his purpose. (Romans 8:26-28 ESV)
The Works of God 
What hope!