The point is how does he accept the situation and find ways to be able to still travel when he wants to, rather than feel stuck at home etc. I would suggest allowing a couple of weeks for that initial getting used to things then into action.
So it would be a good idea to see it as a logistics problem and go through the various situations.
Get the latest up to date bus and train timetables and ask around for friends recommendations for a taxi firm that he could become familiar with.
Look at present hobbies and meetings that he attends, deciding which are the most important to him. Then, if he plays golf or goes swimming with friends , perhaps he could arrange for them to pick him up. He needs to pay half the fuel and also be on time, when they come to pick him up. That way it is likely to become a regular thing, in a way that is fair and suits every one. Perhaps there is a more local club that he could walk to and change to that one?
Then he could enjoy some research into things like pub meals at lunchtime. If he finds a bus route that will take him to somewhere good, that will give him another independant way of going out etc. Of course he will then be able to have a drink with his lunch as he is not driving!! Then he could perhaps look around among friends to see if there are 2 or 3 more people who are no longer driving and they could share the cost of a taxi to the local town or market on a regular basis?
Dont forget there are some pluses about this. If he goes by bus, then if he finds the meeting boring, he has the great legitimate excuse that he needs to leave early to catch his bus. Something planned he isnt interested in? Then he can say sorry he cant get there with the buses etc etc. Of course he should be getting great use from his free bus pass, and on a nice day could just catch a bus as the whim takes him, visit the busiest of towns without thinking about the parking etc etc. These are only ideas and I am sure once he gets going he will have lots of ideas of his own. He might enjoy having a little notebook and keeping a tally of miles he has travelled free gratis and for nothing! Always adds to the pleasure