There are a lot of types of anxiety disorders. The problem is, the more a person isolates themselves, the worse it gets. The constant onslaught of social media and news has increased the number of people who do not leave their homes for fear of death or other issues. No matter how unrealistic these fears may be, you cannot necessarily change the behavior. If he is working full time, then he is interacting with other people. As far as having friends to hang out with, he is too old for play dates. He cannot drink while on the medications and so the club scene is not a good idea (not that it is for anyone). Your best bet is find something he likes to do and see if you can get him involved. I was surprised to find that there is a group of adults in my area that are doing Pokemon go. It's not my thing but, the point is there is a group for everyone. Counseling might not be a bad idea. Make sure you know the side effects of his medications and what he is taking. Physical activity is important. Physical activity empowers people and helps the brain create positive chemicals. The walking is good, maybe his Dad can figure out something they can do together to increase exercise. This also might get him out of the house; golf, fishing, anything really.