Originally Posted by
offerendum
I think you are too pessimistic. If he isn't a totally helpless person, it will be fine even with changing trains. Munich is the city in Germany were the most people (Germans to be clear) address me in English. Also you don't leave the train at the wrong station by accident, especially as the airport is normally the final destination.
I talked to him yesterday and we decided he would stay at the Airport Hilton. It's surprisingly affordable for an on-airport hotel, it's not going to be much more than staying in an area hotel and having to pay for transfers between train-hotel and hotel-airport. Not to mention the convenience. And he can go right to the airport from Regensburg. If he had more time, he would love to stay in downtown Munich and explore for a day but he works until mid afternoon on the Tuesday and the flight is late morning Wednesday.