One thing that gets my goat about Doug's ex-wife is her occasional references to her maternal ancestress as "Rosie," as if either (a) they're best pals, not mother-daughter or (b) Doug's ex-wife secretly sees her mother as a pet rather than a person.
There's a good reason the 6th Commandment, about honoring one's parents, exists; if one is incapable of respecting one's parents, one is incapable of self-respect.
I suspect Doug's ex-wife, like the truemud primitive and some other primitives, is just hanging around Mom, impatiently waiting for her to die, so she can get the cash.
I don't think Rosie's demise is going to be very lucrative. If she had any liquid assets, it's unlikely she would be jammed into that little camper with poor stupid Beth, her two big smelly dogs, and (maybe, maybe not) her mentally ill son. The used Airstream is very old, according to Beth, maybe worth a few hundred bucks. The abandoned goat farm may be worth something someday, but today, after the California real estate crash, it's virtually worthless, or else Rosie would have liquidated it and bought a place to live. And poor stupid Beth will likely have to share what little inheritence she gets with her crazy brother, plus any sane siblings she may have. So, she'll get a fraction of what the camper brings on Craig's list and a bunch of cashews, and then have to find a place to live. Maybe her siblings will allow her to keep the trailer, since it's worth very little, but I doubt it, since she seems to have been perpetually at war with her family.
Poor stupid Beth's best bet for making money would be to run her kid's drug dealing business while he's in the slammer, but she's way, way too stupid to ever run a business.