H.L.
I will keep your family in my prayers, especially your little girl.
Onto your request, I am just guessing here but it sounds like he is having trouble seeing his baby sick and/or in pain. He could be blaming himself for her illness and staying away so he doesn't hurt her anymore. Maybe being away is how he handles it. I think you just need to ask your husband why he is being so distant with the family. That is the only way you are going to get answers. It sounds like the both of you need to work on your communication skills so you hear each other.
Good luck, and I pray your daughter beats the pants off of the Cancer!