Boyfriend with no friends?

When I first met my boyfriend he had a small group of friends, about 3 reallly solid ones. We've been together for a while now and since then he has removed them from his life due to various reasons; mostly drug related. They got very heavily into drugs, started using and abusing my boyfriend and since my SO is not about that life, he has since dropped them, deciding that they are in two different places in their lives and is fed up being their doormat. He has been a bit depressed since this has all happened which is completely understandable, I just want so badly to help him.. :( If he didn't have me he would literally have no one and I hate that he feels that way. He is such a great guy and deserves all the happiness in the world.. what can I do to help him make friends? He works in a job with a lot of older people and works full time so it's hard for him. Please help, I need some advice :( I don't want him to feel so alone and am worried it will effect our relationship down the line ..