Can anyone provide me with info on Buster Douglas dad who was a fighter?

That undercard was even more interesting after a bit of research:

Ray Lampkin was the No. 1 contender at lightweight and Vilomar dropped him twice — in the firsts and ninth rounds — to pull off the upset.

 

You are correct. It was just a knockdown at the end of the day. There was a controversy around it. The way Monroe grabbed Douglas on his way down he sort of melted to the canvas. Douglas's manager Bruce Trampler protested saying Monroe's knee was on the canvas and he was down longer than 10 seconds. I totally forgot this.
The protest went nowhere and Monroe won a decision.