Chuck hitched a ride on one of the spare Solgaleos and made his way back through Ultra Space to Alola, then had Azriel teleport him to the Poni Island Pokemon Center.  He left his Pokemon with the Nurse Joy to get healed up, as well as letting Cosmo get looked at, while he rested in one of the rooms while his Lopunny, now named Hibiki, looked after him.