In Search of a Recipe for "Pepper Vinegar"

I'm really hoping you guys can help me. Normally I'm pretty good at googling whatever I need to find but this one has been a struggle.

I live in the South and my 74 year old boss is a classic southern gentleman and likes to eat as such. He loves "pepper vinegar " on a variety of foods, from collards to ten bean soup. The lady who was making it for him for years died and he's been lost since then.

I am not a cook, but I try to cook what I can for him, with the help of recipes I find online. But I haven't been able to find a recipe that he says "sounds right". All he can tell me is that it has peppers and vinegar. He doesn't know what type of peppers. He doesn't know what type of vinegar. He doesn't even know the color of the peppers, except he thinks they "may be green or yellow or maybe red".

He says it's not too spicy, but has some heat to it. I found some "pepper sauce" made by Tabasco and he said that was way too hot. I found some pepperochini in vinegar, and that wasn't hot enough.

Any suggestions or guidelines or hints from anyone would be greatly appreciated!

bon appetit