Geralt frequently rescues and protects people, but has no real ability to heal them if they're deeply injured. If you wanted Apollo to do some healing, Geralt could seek him out or bump into him when searching for a healer for someone he saves? I'm thinking probably a child (either a boy or a girl depending on what vibes with you; I know Apollo is also a Dad and so is Geralt).

I think he'll have a lot of sympathy about bearing burdens, and I feel like they could have Conversations after the event is over.