I have 2 Maine Coons both males born one week apart and from different liters. I have had many Coons and know all to well how to deal with them, yet the younger of my two just started urinating in the water bowl and pooping in the food bowl. Also will urinate in liter box, but won't poop in it. I feel I'm dealing with a domination issue. Yesterday after he pooped in the front room I closed the door cutting of access to that room. As a result he took it out on me coming home to find that he pooped, and urinated on my bed. Let me tell you this is what I've been scared of this cat is around 26 pounds and his brother about 18 pounds. What do I do?
You might want to check with your vet to rule out any medical issues first.
It sounds behavioral, especially if you have two intact males. I get them neutered before they start spraying. In multiple cat households, you should have a litter box for each and a spare. I'd let him stay in the bathroom while you are gone or a large wire crate would be good too.