They'd waste their own time and probably have to restructure their house to keep a 600+ pound whale contained in there.
A new shower with hand rails/a seat because the Ham won't be able to stand soon enough (I would opt for a kiddie pool in the yard as a cheaper option), probably bigger doorways, a king sized bed to fit her ever-expanding body, constantly catering to her every need, bathing/wiping if Becky becomes too lazy to do it for her...
No sane people would ever volunteer for that, if I was Becky's family I would sooner disown her than let her bring AL into my house. Besides that they're pretty homophobic from what I've read, so I don't think there'd be a chance even if AL wasn't who she is.