Oh no, Louis is in peril.

I would have never suspected a cat to act like this.

Look, I think I might have been wrong about your cat.

At first reading, I was thinking he was missing Henry.
(this is what I get coming in on the tail end of something)

but reading your one line summary...tonight

I'm glad if you have stopped him from peeing on things.
Now I'm thinking, he's just marking his territory.

He may have had zero affection for Henry. I don't know why, but I was
thinking they were long time friends or something, like salt and
pepper, like the ocean and shore.

You know this already, he's marking territory. Now he's the king right.

I would think in time, you could wean him from meds, by re-assuring him
that he is the king, and for that cat...he may not let you bring
another male in the house. Where'd you get the idea to put to males in
the house?