So is Father's day an ignored holiday at the mansion or do all the grunts treat Guzma like their 'dad' and shower him with gifts and he in return he tries to be better than his dad by doing everything he never did for him?
There’s no Father’s Day in Japan, and obvs Alola isn’t Japan, but it’s not America either? So there might not be a Father’s Day at all? Really depends on your own headcanons there.
Personally I don’t think Guzma would want to be identified as a father figure. We’ve already seen that he’s kinda uncomfortable calling the team a “family.”