If you had the ammo to destroy a coworker who is a known bullys career would you do it?

Before i retired there was a guy who was a jerk to most people. Know it all thought he was better than everyone you know the type. Him and I had a few run ins. I reported him once before about his treatment of others and myself. However i slowly found out about time theft and other things that could have landed him fired. Mainly things he has said to other people.

One day he came in loads nicer and stayed pretty decent. I heard he never had time to grieve after his mom passed last year and had a horrible job before he came to work with the company i was at. He said he was in therapy. It was because of that I never brought the hammer down. He showed progress in attitude and treatment of everyone so I put the hammer down.