If they are really friends, his temporary speech difficulty will not make any difference. Do not force him into social situations or into large groups or crowds until he is ready to accept them. Sometimes it is better to begin in a small way with a few friends in private gatherings. His success here will give him the confidence he needs to move on to larger and more varied situations. Many times his children, and especially his grandchildren, can provide some of the successful experiences he needs to feel in gaining the confidence required to face the world once again.
Kids are just great.
It is not uncommon for them to even try imitating his way of speaking. Their complete acceptance is a beautiful thing and can help him to accept himself if he is having difficulty in this area. He can t help but be inspired when he sees the tremendous things that others who have had the same experience are doing. If he won t go, give someone from the Club a call. Time is an important factor.