Sound like an awesome gift!
You don't need a new little brother do you?
I'm already big brother broken!
But yeah, sounds good.
The only thing about the SM7B (and this is from reading about it, not use) is that it requires a lot of gain.
The Apogee Duet has 75dB of gain if I read correctly, so you should be good.
Wait for someone who has used it to chime in though.
After that is sorted, he'll need a place to actually record since the room he records himself in can impart itself onto the vocal.
Don't worry though. There are lots of cheap DIY things he can do with things around the house versus buying room treatment, which can get expensive.
Anyway, hope everything works out!
"I don't have to dodge shots, I'm the shooter".