At one time I had a job that involved a lot of entertaining. The industry had a kind of tradition of hard drinking with the salesmen and the customers so it was a bit strange when I came along. When my customers noticed that I wasn't drinking, they wouldn't drink either, and I noticed they were having trouble relaxing, so I often insisted they should not give up their pleasure just because of me.
Obviously, the boozy celebrations when a sale is made were not going to work with me, so I changed startegy. Most of my customers were small businesses and there wives had a big say in how they ran the business. I began taking the customer and his wife to nice restaurants which made the whole evening a lot more constructive.
The wives appreciated the attention but also enjoyed not having their husband arrive home drunk. There were benefits all round. I found after a while that when it came to my products, the wives wouldn't let their husbands buy off anyone else. Just shows, not drinking isn't a handicap in personal relations, it can be a huge advantage.
Fartogo, maybe your friend just felt uncomfortable at the idea of drinking alone. Sometimes people feel that way, it's no big deal. Sounds like you handled it fine.