Yeah, Toushirou and Hajime had by far the easiest reactions... probably because both of them knew it was him without introduction thanks to their ability to sense him.

But yeah, from what Phillip knows of Toushirou's Granny, he's sure it'll be fine. She trusts Toushirou a lot and lets him do things. As for him... "I haven't told anybody in my family yet. I'm probably not gonna." His grandpa knew, and that was enough, and... his parents probably wouldn't let him leave the house ever again.