I would not lie to him if I were you. His trust is much more important than lying about it. Sure he might not but if he does find out, he may or may not trust you or sell you any more birds. It's sad it had to happen and alot of good breeders going underground or rather not deal with BYC members.
However if you know if he joined in some breed clubs, you can tell him that you found him in (breed name) website and wanted to know if he has some for sale. I do remember he has not had that many birds like he used to. Sad, isn't it? He got some good birds.
Once in a while you can find him in flea markets or poultry auctions or poultry shows that he likes to visit. One day you guys will catch him and he probably would do business with you. He has been a wonderful guy and I've bought eggs and birds from him and they were all excellent! Just ask around if anyone knows him and where you can catch him.