He is grieving a loss in his own way. A divorce is a loss. He sounds like he was fucked up before but now more so. I was fucked up but being emotional has always been my thing. Aware of how I am as well. Hopefully he will just fade away and not bother you. But some are in denial or disbelief. He does not sound like any history of violence so that is a positive. Being an asshole is hopefully harmless in this case.