I made reference to Jerome using a small amount of the drug after he got his throat slit when he was a teenager - and since Hushed didn't seem to have any issue with it, I assume all the families have had some encounter / stock with said drug. How else would they know it's valuable?
But, like Nothing said, all powers can be used in a overpowered fashion, or a under powered one. I know a guy who played an assassin who's only abilities were parkour and the ability to turn into liquid goo, and then re-materialize again. And that thing was the bee's knees.

Anyway, RE how Jerome could heal empath abilities - he just couldn't. He might prove to be more difficult to manipulate due to strong self-discipline not found in most other people, but his powers would have no affect on it what so ever. They heal cuts, bruises, broken bones and keeps his stamina up so he won't tire out over an extended period of time. Of course, to a reasonable amount. With a regular use of the drugs I suppose he could become the equal to Wolverine or Deadpool, but that's not really what I'm going for.