How to deal with someone who has an eating disorder and narcissism issues?

I live with someone who has body dysmorphia. He also has cancer and very narcissistic.

Everyday about 3-8 times a day when in his presence he will gloat about how happy he is that he’s not eating much or has done multiple hour long work outs, is losing weight drastically and act really shocked and upset but actually thrives on it and gets excited when explaining it? The doctors are worried as he’s lost 8 kilos in 4 weeks and lies to them saying he’s not trying and it’s because of the cancer he’s throwing up, etc. But actually he works out 4+ hours a day and eats one thing a day.

In terms of the narcissism, he thinks every girl who even smiles at him or is polite wants him 🤦🏻‍♀️ there’s a woman he really likes across the road who is just genuinely nice and isn’t interested very clearly but because she’s being nice he thinks she wants him and when she doesn’t answer his texts or talks when she sees him he comes back angry, saying she’s prick teasing him or playing hard to get but actually has a boyfriend and has rejected him asking her out. Is his disorder causing this or maybe like something else? He’s obsessed and it’s kinda scary as it’s been over a year he’s been like this about her, spying on her flat, spying on her when he sees her out and constantly plotting ways to get near her, talk to her and even with his ex girlfriend they constantly talk on the phone about her and plot shit 🙄🤦🏻‍♀️ it’s so so weird and I’ve tried getting help mentally for him but in my area you can’t refer and adult to mental health services only they can, even if a danger too themselves.