Give a 6 year old his own room

My son is 6 years old. Over a year ago we discovered extensive water damage in the floor and wall of his room. He has been sleeping on a mattress on the floor in his sister's room since then.

Our homeowner's insurance refused to cover repairs and subsequently dropped us from coverage. We can't afford to make the necessary repairs on our own and it breaks my heart that my son doesn't have his own room for his toys and clothes.

The roof must be replaced, as well as the floor joists, flooring, back wall, and windows. Anything you can give would be most appreciated.