There are no words, but please know you haven't left my thoughts. I know it is impossible, but I'll give you the same advice I got from a friend when I was feeling guilty about the time I spent away from my daughters while handling their sister's medical needs: She needs you more right now and that's okay.
Continuing to keep you in my thoughts and prayers.
It's OK to choose her right now. It doesn't mean you love her more, it just means she needs you more. I promise your son will never look back and think that you should have been changing his poopy pants while your daughter is going through all of this. Never.
You may not post often, but we are here for you. As a place to vent, a place to come for some extra support, and a place to help you find resources near you, if you need them. We are all moms. Our hearts ache for you and your daughter. We want to make sure you know that you have lots of support, prayers, positive energy, good thoughts, etc right now.
I'm continuing to keep you in my T&P. Please don't feel guilty in relation to your son- your daughter needs you more right now, and that's ok. Hugs to you.