Selheira
Truthfully, the old-young man hadn't done much other than bring Ryu to safety. As for the healing process, Ryu's own body dealt with that.
However, strictly speaking, he was saved. If his half-dead corpse was left in that location, then he would have ended up being ravaged by the next beast that came across him. There was definitely something to be said about that.
There was only so much protection Little Silk could have given him. He still wasn't even very familiar with the little one's abilities. The little butterfly was basically a glorified seamstress. Though, now that Ryu thought about it, Little Silk would make an elite Spiritual Seamstress. Or, at the very least, a very sought after familiar for someone in the profession.
Ryu didn't know what changes his mother had made to Little Silk, but since Himari had gone out of her way to give the little one back to Ryu, it definitely couldn't be simple.