(Former) Partner with ADHD "Can't Form Personal Connections"

Those are his words, but I believe they're accurate.  He told me this weekend that he knows this is true because he prefers sitting with his mom, who has late-stage Alzheimer's disease and can't process communication, than being with his dad (and, presumably, with me). In a way, this doesn't matter anymore (we're now divorced), but it still hurts.  I wonder if he ever told any of the several therapists he visited over the years that part of the problem was his inability to form connections and it wasn't only my fault that our relationship was rocky and his life wasn't going well.