First, this game is weird when people can limp in.
Not being a d*** just FYI people would refer to this as "jack low." If you're just playing it online no reason you'd care.
Easy fold. Later in tournaments you'll have plenty of uncomfortable spots where you have to decide whether to just go with a rough hand like this, made worse by being OOP. But why do that this early? Probably a common misconception when people start playing lowball that they have to play jacks. You don't.
Over-shoves like that (tho not huge given effective stacks) often scream rough jack but in this case he could be doing it with the best hand. Anyway, it's a rough pat in position or a great draw. If the latter you aren't ahead by much so no need to risk your tournament on this hand.