SUBREDDIT: r/relationships
TITLE: My boyfriend [23M] and his younger sister are getting kicked out of their home and I [21F] don't know what to do
POST: They both live with their dad and their house has been for sale for ~5 months. Last Sunday they all went out for dinner when his dad announced that he and his new fiancee are moving in together and there isn't enough room to house them. They have about 2 weeks to find a place to live and are understandably freaking out a bit

His mother is a very successful lawyer, but when I suggested he ask her for some help, even if just for a month or two, he shot it down. They have a complicated relationship and he's not her biggest fan. I then suggested he ask some of his family members for help or a place to stay for a while so he can figure things out and he replied that he doesn't want to inconvenience them and that even just asking would be rude. 

He's still in school, his sister is still in high school, there's no way they can afford anything halfway decent on such short notice. I'd honestly offer to let them stay with me, but I still live with my parents.
TL;DR: 
My boyfriend and his sister are getting kicked out and refuse to ask for help from his family. I feel helpless and have no idea what to do to help/if I even should. Help? 