How to stop inappropriate behavior peeing outside?

Then he can't be outside alone. Apparently this is someone with dementia. You just aren't going to be able to fix him...so as these kinds of inappropriate behavior present, if you can't stop it, then just be prepared for it to happen.

If someone is with him,hopefully they can cajole him into going inside. If not, well, just grin and bear it. That's sure what
I'd do.

It's been my experience that guys are a bit different about peeing outside than women . . . Even without dementia.

Hang in there. Those that notice, if you are given an opportunity to explain, will be fine with it.

There but for the grace of God goes me . . . And you.

Lot of guys won't see anything wrong, they have done that most of their lives either as a kid, or at other times where a bathroom was too far away to bother with. Here are some other comments about that. https://www.agingcare.com/questions/Elder-likes-to-pee-outside-147797.htm