Reporting animal neglect

Hi, just looking after some advice. I realised a friend of mine has been neglecting his pets and am not sure what to do.

Backstory: He hasn't been mentally well since his wife died 3 years ago but won't take meds his doctor prescribes or go to therapy. He has 3 cats, 1 elderly dog, 2 birds and fish (not sure the amount).

Situation: he is feeding his cats and dog one 160gm can cat food per night between all of them, they are literally fighting over food and wanting more, the poor dog whimpers at night (assume upset stomach), I am not sure if or how often the birds are being uncovered or feed (cage outside) or the fish (downstairs in the garage). They (the ones I have seen recently) seem ok but undernourished. He lets them pee and poop anywhere and cleans it up with paper towels later.

I have reached out to my vet and animal rescue places and basically being told submit a request with RSPCA, but it prob won't count as bad enough for anything to happen.

I have tried talking to him about it but he brushes it off and says he will get it sorted but hasn't and it's been months.

Any advice?