What is the opinion of Reddit about the
Bright Guard 2.0 Adjustable Night Sleep Aid Bruxism Mouthpiece Mouth Guard?

This helped me: Bright Guard 2.0 Adjustable Night Sleep Aid Bruxism Mouthpiece Mouth Guard https://smile.amazon.com/dp/B07NHG4R7D/ref=cm_sw_r_apan_glt_i_ZK3Z3MK1JWYJ6FZNPEKB?_encoding=UTF8&psc=1

Everyone is different, but have him try it if he hasn’t already! My wife appreciates it too 🙂

No problem. This is one that will work:
https://www.amazon.com/gp/product/B07NHG4R7D
The idea is that you extend the lower section (jaw) a few mm out which also pulls your tongue out. This one is a bit bulky but you do get used to it.

A slimmer version is called SnoreRX (I don’t think you can buy it on Amazon) but it is more expensive.