It was inherited (though it seems to skip generations- after some digging he found out his great grandmother and a few ancestors before her documented the same phenomenon), but it only manifested after a certain event involving a certain suitcase that occurred during his childhood. He doesn’t require the suitcase to do it, but the item has become something of a security blanket and he generally fares better when he has it around… it’s also pretty exhausting, so he can’t easily use it more than once a day. Perhaps someone could help him to have a higher tolerance with some spiritual training of some sort… 

I am also way, way too into this.