I think you just can't see it as a jacket, but as an accessory. Just like many ladies wear their lambskin or faux leather jackets to the office.I mean good for him, but it's being worn like a fashion jacket
It's definitely too small. The gaps in the lapels being that far apart makes it seems like he won't be able to zip it up unless the back is like a tent.
Sleeves also too short ending a decent distance from the wrist.
And then it's all right again. Everyone as they like.