It depends on what's causing it. If he has social anxiety disorder, for example, then telling him to just go for it probably won't work, and he needs to go to therapy or do something that's capable of addressing it. Now I also wonder if he has strong meninist circle who are at least a generation or two older than him, because if he doesn't, then he might want to build up that first, because their strength and courage and resilience and confidence will rub off on him.