Stop in for a cup of coffee

Aint families great!
My son went through a few years of extreme party phase, dropped out of college etc. Hasent lived at home since going off to start college, so he has managed to keep a roof over his head through it. Hes 24 now, works full time and getting his act together.

Picked my daughter up at college yesterday. Shes doing really well. We stopped at my Dad's on the way back...
My sister (48 yrs old) lives with him. He is 85, has lost sight in one eye and numerous medical issues that limit him. She has been on disability for years for 'abdominal pain'. I dont doubt she has an issue, but I have no clue how she continues to collect. She will have a huge problem getting work if they cut her off.
They share a large mobile home. Bedrooms on opposite ends, so set-up is pretty nice for 2 adults. It was in excellent condition and about 10 years old when they got it 16 years ago. She got the master bedroom end with its own bath. Her area is COMPLETLY TRASHED. I pulled the tub out a few years ago because it was cracked and leaked. ( she never bought one to replace it) The moisture from that destroyed the floor through here room and some warping and soft areas into the next room.
So now the roof is shot. Dad said he has $ to replace it, but with the damage she had done to the inside, i need to figure out if its worth more than the cost to fix it.
I'm encouraginghim to find his own place, but i dont think he will. Sorry to say, but Dad wont be with us forever and shes gonna have a rude awakening...