Have your aunt’s froslass comfort him if you can.
I know this seems counterintuitive, but your snorunt may be more willing to listen to her, and she, as a member of the snorunt line, may be in a better position to understand his emotional needs. Also, giving your snorunt a mentor will provide him with not only a means of uncovering his potential as a (perhaps) future glalie but also give him some life guidance in general.
If it’s not possible to get your aunt’s froslass to mentor him, finding any similar pokémon (preferably an ice-type) will work too.
Finally, if he still needs some comfort, even after these pokémon offer, many outlets sell snorunt-sized froslass costumes this time of year (or you could make your own). It’s worth a shot.
Best of luck!