OP I think you’re getting a bit of a hard time here. I can totally understand that some people who have worked in one place with a short walk to work will be completely thrown by having to consider a 20 mile commute. While the latter is normal to many of us, if it’s something you’ve chosen not to do up until now and is then forced upon you, I can understand how for some people this could be an enormous stress. And, I say this with kindness, if you have been at the same place for 40 years, that does suggest you are not a fan of change.
Having said that, it’s unfortunately a normal part of working life now so he needs to decide what he wants out of it. Doing nothing wont make it go away and will most likely increase the stress he feels under.
Based on previous experience, I’d certainly be expecting them to provide some kind of travel subsidy for a fixed period of time up to 3 years. I’d also be looking for a season ticket loan scheme if he would be using public transport. Could he change hours to suit the commute - I’d do 7-3 if I could for example, to miss the busiest time. Is early retirement an option? If it was me, I’d be making a list of what I wanted and then would start negotiating. It sounds like it is going to happen regardless, so he has nothing to lose at this point.
If he’s within shouting distance of normal retirement, I would probably suggest just getting his head down and getting on with it for now. Definitely don’t resign though. Not until he sees how it pans out over the next few months.
As an aside, what are other people in the office feeling about it? Are they ok with it or are they unhappy too?