Bpd and Autism

Ok I have a son who has  Asd and another who is under pychy who supposdley has Bpd, now this evening I have been doing loads of research to find out a lot of autistic people are being diagnosed as bpd when they are in actual fact Asd, I have mentioned this to my sons coordinator in the past to get him tested for Asd but nothing came of it.  Just to say though when he first got sectioned the hospital said he had Asd, but I have heard nothing of it since.  He fits the criteria of Asd more than he fits bpd, I just wondered if anyone else vould give me some more info.  I seriously feel like them telling him he has Bpd does not fit, that does not mean I do not want him to have it, but it does not fit if that makes sense.