Stop in for a cup of coffee

Not much to sue for.
What would be the claim?
Sure he touched him, or was abusive in the way mild hazing is, but really not much of a case and a lot of hassle.
If there's some impropper practices - like age discrimination - then report to the state or fed agency that deals with such things.
There are laws that prevent companies from coming after people for reporting to HR. Illinois is one such state that has those