I am a professional orchestral musician, and I can tell you that it has been proven that orchestral musicians will lose at least 20% of their hearing over the course of their careers on average. It is a very unfortunate side effect of the job, and it is therefore no surprise that your father is experiencing it, Audphile1. They do indeed sometimes use clear panels (plastic, not glass, though) in between musicians, but most of us actually do not like this much as it hampers visibility. I should wear ear plugs more than I do, and my orchestra provides us with the cheap foam ones - there is always a big box of them on hand. Of course, you can't hear yourself or your colleagues nearly as well when wearing them, which is why many of us don't much, despite the certainty of eventual hearing loss. I myself usually only use them for pops concerts when they amplify everything to ridiculous levels anyway. I really should go and investigate the more expensive types mentioned above - the orchestra has a deal with a local Jones outfit, I've just never taken advantage of it. I would add, though, that if anyone thinks ear plugs are necessary for home listening, that very probably they simply have their volume cranked way too loud.
