Pretty common in households for parents to just not think you can hear them talking about divorce and sensitive topics like that when their child is just in another rooms and stuff actually I've seen it myself
Meh I think he just calls it healing magic cause he has no idea what else to call it (this was mentioned a lot in early chapters) the magic itself seems more akin to life manipulation magic that controls genetics itself and can create various implications of life it's a power akin to god