Protective big bro Theseus, yes! He doesn’t doubt Albus’ intentions – much – but Newt is just too young for this, it has consequences Newt isn’t thinking about, of course he doesn’t want his little brother expelled but he’ll teach him magic his own damn self if he has to, this just isn’t right.
But the rest of his family doesn’t want the shame of their son being expelled, and maybe with a marriage to such a powerful and prestigious wizard Newt will turn out being good for something anyway. And Newt wants this after all, he’s practically begging to be allowed.
I love the thought that in some aspects Newt isn’t even aware he’s being trained. It’s pretty clear the gloves are a punishment, yes, but what’s not so obvious is when he starts to associate a touch at the small of his back with being reminded to obey, or a squeeze of his shoulder with being asked for silence. What’s not so obvious is how tense and anxious he gets when Albus refuses to touch him at all, and sags with relief and tries even harder to obey when Albus eventually relents.
Theseus can see it – the way Newt starts looking to Albus for confirmation or permission when he talks, how so many of his sentences end with “I’ll ask if it’s okay,” when Theseus tries to make plans with him.
Newt doesn’t see it, he doesn’t want to, and it simultaneously breaks Theseus’ heart and fills him with frustrated anger at the situation.
I wonder if Theseus would try confronting Albus about it once it’s clear Newt won’t listen?