I've been reading Frank Schaeffer's Crazy for God and came across this passage about praying for his premature daughter:

With [my daughter] not keeping her food down, I learned the prayer that has no words, the one I'd be praying forever after I became a father, whatever I called myself, or converted to, or abandoned, when the feeling of dread is prayer—prayer longing for what I could never give a child in danger, or myself: the guarantee of joy.

After reading that, I had to stop and soak in it for a moment. My boys have been very healthy but I can relate to that feeling of caring for these little ones and wanting the best for them no matter what. Ultimately, the only thing you can do is pray, asking God for his protection and that he will call them into His fold.