I wouldn't.
1) You never know who will have an addictive tendency beforehand
2) If he is like me, those things make my brain foggy and move it outside my head. I will avoid any opioids unless I would choose suicide to stop the pain otherwise.
It works to a degree and for sound levels, duration and frequency the average person would encounter. I found that a blender is 90 dB, that is pretty loud but most people don't run their blender for hours every day. One really needs to use hearing protection in their everyday activities with loud machinery.
I suspect Bob was relatively close to the F-16s with some frequency for extended periods.
Years ago when we would sail on Lake Champlain and the SAC base was still at Plattsburgh they would fly F-4s over to Burlington (we have an Air National Guard base). Those suckers were fairly low given the distance is only a bit over 20 miles as the jet flies, they didn't gain altitude as they would if they were going somewhere distant. They were LOUD. They were loud coming but as they passed overhead and you were on the exhaust end of the plane it was seriously painful.
And the Blue Angels F-18s! They did an air show here some years ago and were practicing the day before . Their path was over the lake but the house was close to the lake and as they crossed over land to make their turn back to the lake they went right over my house. And I mean RIGHT over the house. Look up and there was the plane low. It hurt. I went into the basement under the garage which we had dubbed the "bomb shelter" - poured concrete walls and garage slab. The only opening was a 5' wide entrance from the basement under the house. The F-18s were still loud in there, louder than my circular saw. Fortunately we had somewhere far away to be for the weekend and didn't have to suffer it again.