Well, I am probably not the best to weigh in here, so I will keep my personal thoughts to myself and advise that you follow your instincts in your dealings with him.

know that at some point it will most likely get nasty. doesn't mean it will remain so.

I don't think you necessarily have to tell him anything. you could say this is a shock and you're trying to get your bearings. stall for time.

M 20+ T25+
S ~15.5 (BD)
BD 4/6/15
D 12/23/16

"Someone I loved once gave me
A box full of darkness.
It took me years to understand,
That this too, was a gift."
~ Mary Oliver