Did I get hacked or is this a glitch?

My brother just logged on, he lost a Versalmas Hat, Stirgeman pants and other stuff. But none of his mesos was touched. His key configuring was also messed up. None of the other characters were touched.

Also, on another one of his accounts, he has a level 35 Cleric, which he hasn't used in months, suddenly has 3 Slime Shoes instead of one.

All of 'em are in Windia. Only affecting the highest character on the account.