My brother-in-law was in debt when my sister met him. She got him out of debt, they got married, they got back into debt while she was working full-time to put him through undergrad, and then she got them out of debt again while she was going to school part-time and working full-time to complete her own undergraduate degree. BTW, both chose some horrible degrees when considering future employment - political science and theater, respectively. They had a kid despite not having great jobs, got back into debt due to BIL's obsession with going to concerts and buying vinyl, moved to a higher COL area because BIL is perpetually dissatisfied with everything, got pregnant, bought a fully-loaded minivan because of kid #2 (WTF?!), and finally moved in with my parents while my sister was pregnant so they could get rid of their debt.
BIL posts FB updates regularly about new purchases, like a vintage record player (not working), assorted albums on vinyl (usually multiple copies of stuff by indie artists that believes he's going to flip for a huge profit - "that's my kids' college fund right there"), etc. Last month we were at my parents' house, and the basement where they live is overrun with toys, trinkets, record albums, and literally hundreds of concert T-shirts. He has gone to three concerts in the last month, all at least an hour's drive away. Sis is currently staying at home with the boys while BIL commutes an hour each way - my parents live in a rural area - to work, driving the minivan of course.
I've tried to point my sister to MMM and other blogs that might help. She wants to do it right, but my BIL is hopeless and drags her down, which she constantly enables. They asked their pastor for advice, and he told them to sell off the vinyl and other collections and eat rice and beans for a while. "Can you believe that?" BIL says. "Who could do that? Stupid." I mostly feel horrible for the two kids, who are learning some very bad behavior from their parents and their grandparents - my parents are hardly models to follow financially, since they've been in debt for about 30-odd years now. My sister, if she ever pulls out of her depression/funk, can right the ship, but she may have to throw BIL overboard to do so. Sucks.