AITA for not paying my neighbor for mowing my yard?

I (33M) moved into my current neighborhood about four years ago. One of my neighbors (50sM) has lived here his entire life and is a bit odd. I’m not trying to diagnose him, but he clearly has some emotional and learning disabilities. But the thing I want to talk about is his yardcare obsession.

In the summer, he will mow his yard every day. Occasionally twice a day. He’s very particular about his grass and has confronted me about the trees in my backyard dropping leaves in his backyard. After I explained that I can’t do anything to prevent that, he began raking all the leaves in his yard and throwing them over the fence into my yard because they’re my responsibility.

When I moved in, my neighbor complained to me several times that my grass was too long. It was a bit shaggy but it wasn’t tall by any means. Either way, there’s no HOA here so I can keep my grass how I like. I told him this, but he just insisted that I needed it to be cut short like his.

My first year here, he’d repeatedly ask me to mow my yard more and I’d say no, that my roughly weekly mowing was fine. He was obviously frustrated that I was blowing him off but I’m not going to cater my yard to his preference.

I also have a suspicion that he reported me to the city for having grass that was too long. A city worker came by and told me someone reported me for having long unkept grass with rats living in it. I showed the city worker my backyard and he shrugged, said I was good and left.

This leads me to the point of the post. He began mowing my front yard himself, presumably out of frustration. Typically twice a week. I’ve asked him why he does this and he says "somebody has to." I’ve asked him to stop and he was dismissive.

So now he’s just kinda my volunteer gardener. I still do other yardcare and take care of the backyard. I even now the front myself if I think it needs it. This has been going on for 3 years.

I mentioned this to a coworker and she suggested that I pay him for mowing my grass. I said no. This isn’t a service I asked for or require. He’s doing it himself and if I had a choice, I’d rather he stop so I could have slightly shaggier grass. I especially don’t want to encourage this weird vindictive behavior. My coworker said it was a bad look to have a person with some kind of mental disability work for me unpaid but I insisted that it’s a huge mischaracterization of the reality of the situation, but I see the point she was trying to make.

So am I the asshole here?