The funniest thing about Spardacest is having to explain to the children Nero adopted how their dynamic works:
Nero: Remember Uncle Dante?
Nero: He's my biological father!
The children: That's great! That's good!
Nero: And Vergil is apparently my mother.
Julio: But isn't he Dante's brother?
Nero: Yes, but also his boyfriend? Look, it's complicated.
Carlos: Will Grandpa Vergil let us use Yamato?
Nero: Is that what you care about?!
The kids learnt early on that everyone should be accepted no matter how weird you find them, so they indeed couldn't care less what's up with Grandpa Vergil and apperently Granpa Dante.
And I'm sure Nero has a mini heart attack when he leaves the kids with them, and coming back to them playing with swords and other less dangerous devil arms. And Dante always just shrugs and says how he and Vergil always played similarly when they were kids.