At my wit's end- do I report?

[ChangedAgainJune]

DP is very close to his family. He is a key worker (not NHS, but mixing with people all day long). He's been going to see his extended family members all through quarantine: BBQs, drinking couple of beers inside and so on. His family members would pop in as if nothing, have dinner at ours (regular occurence before Quarantine, too), until one day I have had enough and basically threw everyone out of our house as it was getting ridiculous. Now I am a 'controling b' in his family's eyes. No matter how many times I have asked him not to go to these gatherings, I was ignored. This weekend we have all been invited to family member's b'day bbq. From what I know it could be more than 30 people from lots of different households. I have already said I am not going (once again, was accused of hating his family), DP is, of course, will be.
My question: do I report party to the Police?
All of his family thinks that Covid-19 is some sort of conspiracy and tell me they do not know anyone infected by it. Thankfully, I do not know anyone, too.
AIBU to think that gatherings should not be happening yet?

No, I wouldn't report it. That ship sailed weeks ago - your chance to insist on quarantine flew out of the window the first time you allowed him back in after popping over to his family, or allowed one of them to visit you. Grit your teeth and hope you don't catch it.

To be honest I don't think many people are following the rules any more. We are trying to, but they keep changing and are not even being followed by government people.
The police don't want to enforce it, they have quite enough to do already.

@Scarlettpixie

I would really struggle to be with someone who wasn’t taking this seriously.

I would struggle to be with someone who would even think of snitching on me.

I haven't stuck to the rules (apart from social distancing in public), but fortunately my DP hasn't either.

I personally would report him to his employer. He’ll get a disciplinary. He shouldn’t be working with vulnerable people if he cannot sacrifice his social life to keep them safe.