You might think about taking him off the sweet feed and see how he does. It can't hurt to try . Give it 2 weeks or so to see what results, if any, there are from the feed change.
If he needs extra calories to keep weight on, replace the sweet feed with a hay pellet, alfalfa or alfalfa mix. Give him half and half for a week, then no sweet feed at all. Then wait two weeks to see if it helps.
My gelding quit his "stud" behavior when we changed his feed. It was quite a dramatic change in attitude!
Well I am slowly switching his feed. I've been slowing introducing it to him. Mixing it with his sweet feed and they have hay all day to eat. We have feeders in the field. I forget the name of the second feed but it looks like dog food haha.
But its just I don't like his attitude because he shows off. He knows he's the alpha male.
I'm just hoping it'll change his attitude.