It's a nice thought to buy it for him as a gift, but honestly, if he's wearing it five times a year, that seems like a waste.
I have a relative who buys a lot of J.A.B. stuff and it doesn't look terrible on him. Not great at all, but with tailoring it does what he needs it to do, and it is very inexpensive.
At opening night this year I saw a guy in jeans and an untucked flannel shirt. Black tie was far from universal. Honestly a tux is almost out of place on a regular night, but wear it if you want. My tickets are on Tuesdays and I usually wear a dark suit and tie, occasionally a blazer instead.