I'm having a similar problem with one of the bands I've been rehearsing with recently. A bunch of seriously old-school players with decent chops but no concept of reasonable volume whatsoever. To make matters worse, they turn up the PA to just below feedback levels, and then when they still can't hear themselves sing they never think, oh, maybe the instruments are too loud, but instead try to turn the PA up even further. The lead singer insists on angling his mic 90 degrees to how it should be with the mains, and I have told him repeatedly this is causing more feedback but he does it every time. These guys have been doing this for decades, you'd think they'd have this figured out.
I have a rehearsal space in my home and I will never invite this bunch over to use it, that's the quickest way I could think of to alienate my neighbors. Lucky for them they have a rented space.
I'm at the three-month mark with them at this point and, though I was recruited with the promise of work, there are no gigs on the books. My unstated rule is six months of weekly rehearsals, tops, and if nothing's on the books by then I won't waste any more of my time. That's probably far too generous, but I'm still kind of in it right now for the networking. You never know what might come from something. I like keeping everyone smiling and being easy to work with, myself. But there comes a point...