Spouse’s family not scared of covid

Really wanna get smth off my chest that has been bothering me since covid reached our shores. My spouse’s family regularly gathers at their parents’ house for meals. At max it’s a freaking 16 pax in total including the siblings’ family. The thing is my fam can’t really avoid them cuz the in-laws take care of my child. And i’ve been reminding them about the consequences, be it contracting covid/ getting heavily fined but it’s just falling on deaf ears. So now with covid cases getting higher & higher, i feel more and more paranoid because some of them are in front line services and they have kids attending schools. Everyday i fear that one of them might bring the virus back (and also they seem to like going out to eat) and we won’t be able to escape the covid cuz my in-law is in close freq contact with my child. I feel they are compromising not just their own fam, but the safety of others yet i don’t know what else I can do. I can’t call up authorities myself to “harm” them & obviously I’ll also be implicated for smth I didn’t want to be a part of. Don’t think i can live guilt-free even if they didn’t found out it was me. Yet i kept fearing every single day what if we contract covid through them it’s driving me mad…