My partner lied to me to consolidate a fight?

It's only my side of it, but 3:30 am he gets up comes back and starts chewing my *** out for leaving a cereal bowl out. There were reasons for not putting in the dishwasher: it was running. In the end it went bad and turned into a big fight....over a bowl. This kind of thing happens now and then, we're gay. So I pulled a blanket and a pillow to the closet where i retired. He comes up and tells me that "his prostate cancer has metastasized all over his body and he has six months to live. He did this the first time with the Prostate cancer after a fight, and when I one day approached his doctor about 'what was being done', was given the 'what are you talking about' look. "His prostate is fine". He was there but doesn't seem to remember. I've not gone swooning in yet, what do i do? I could swoon in and pretend and let it come apart in his face. I could tell him up. I could???? Help, he's clinically depressed but an unlivable Soul when like this. Maybe I should leave...