"Mundane father/chaperone things" should indeed be perfectly safe for you to use him for according to your discretion - within reason, of course! We would request that you run it by us if you'd like to have him in play or in use for some form of more active plot which would touch on or act within the metaplot (or area sub-meta-plot) and/or would involve NPCs who aren't specifically Winter's (for example, if the girls were to get into trouble with the local police and he was to vouch for them, we'd wish to measure and pass approval on how effective he'd be and the exact consequences it'd net them) - but again, on the whole, his presence as an NPC may do what it plausibly could!