Painted Black, hello, and welcome to the family! I am so sorry to hear what you are going through It is hard, and sometimes it seems the hardest when they reject us.
I dont know how to answer about your son. People are different, whether BPD or not. Either way it does not sound like a kind thing to do. It is not a characteristic of BPD that I know of.
IMHO, I suspect there may be a fair degree of narcissism involved. My undiagnosed Narcisstic BPD mom used to be quite determined to turn me out as a carbon copy of herself, and any deviation from this norm was harshly punished. So much so that I left home at 16 simply to develop a sense of self. Still working on it
Have you talked to your son how he feels about it? If so what does he say?