Family not taking baby’s health seriously?

Hi! My son is 10 weeks old, I had him right at the beginning of all of this craziness and we’ve been in quarantine pretty much since he was 1-2 weeks old. We are temporarily living at my MIL’s house with my brother in law as well. Our plan is to move once my husband is out of the military in the fall and we can move anywhere we want rather than being restricted to this area. Anyways, at the beginning of “quarantine” both my mother and brother in law were still going out and seeing friends or having people at the house. My husband asked them kindly to stop having people over the house and to stick with social distancing. For a while it worked. Until my brother in law got sick of staying home and kept hanging out with friends and returning home (touching everything and not disinfecting) and my MIL took it seriously and said he can’t stay here if he’s not going to respect the baby’s health. So he moved out. It’s been a week and everything has been perfectly fine. But now he’s back and my MIL is now hanging out with friends and sleeping at people’s houses and then coming home. At what point do we just pack up and leave? We can stay at my mom’s until we find our own place, so that’s not an issue. But am I overreacting? Should I just bite my tongue and just make sure all surfaces are disinfected often and washing my hands before touching baby still? Because a huge part of me feels like I want to cut ties with both of them because they aren’t taking it seriously and I shouldn’t have to continuously ask for them to care about his safety.