My brother has a compromised immune system due to transplant antirejection meds. He was tested about 2 months after his second shot (transplant teams recommendation) and no antibodies in his system. All of us that have contact with him have had the shots in order to protect him as much as possible. I fear many in his category are in high risk.
I understand your reasoning, but you may be actually putting him and yourselves in a much worse situation. I certainly hope not, as many people I know and love are getting these experimental gene therapies, with zero knowledge of what could happen