While generally it IS possible to spread it this way, it's a lot less likely than direct contact. Most cases you'll get it from kissing/intimate contact, however there's still a chance and people definetly can get infected, especially if it's an open sore and he's constantly touching it and touching other things. That's pretty gross.
Follow him around with a can of lysol or some alcohol wipes and clean everything he touches right afterwords as raeanna said. Maybe he'll take a hint
