Sure. It's not hard to hijack someone's password when you're that close to 'em, and even if you're not- it's not like people follow good practices with passwords. Any dimbulb can steal a password, and I'm sure Piche can operate a website control panel. Most web-hosting stuff is pretty dumbed down since every two-bit huckster wants to start a website and get rich on "online marketing" or whatever.
He understands enough to know that he who controls the domain controls pretty much everything. Again, I'm pretty sure he hijacked and redirected furaffinity.net for a while when he was trying to pry it out of Alkora's hands. I seem to remember reading Alkora ended up letting go of the site for probably a lot less than he should have, probably because Piche waved wads of government welfare-cash in front of him and knowing Alkora, he probably needed the money.
Sean Piche is a stupid, stupid man but that doesn't mean he's incapable of intentionally screwing someone over when he thinks it will get him what he wants. He's dumb AND malicious.