I can say that there is a lot of mental disorders in my family. I had an aunt with schizophrenia, spent most of her life in mental hospital. Her son committed suicide when he was 21 years old. My other aunt had three children, two of them committed suicide, we think they were bipolar. I have ADHD and I have four kids that are ADHD. MY brother has had addiction problems most of his life. He recently went to rehab, got clean and was diagnosed with ADHD. He too had mood swings and the doctor said could be caused by anxiety. Not sure what they gave him but it has helped with that. The rest of us take Adderall and it has changed my life for the better. I knew I wasn’t dumb but felt like it in school. I could read, write, and was good at math. I just had problems reading what I read and remembering things. That caused problems in English and most of my classes. I had problems with relationships, organization, time management, ….. After I got diagnosed and medicated I was overwhelmed with emotions, the way I was thinking, I went back to school and made the deans list. The difference was like day and night. It was like my brain was in hibernation for years and woke up.
To answer your question, it is possible that he could be bipolar and you ADHD but also you could also be both. Most people have more than one disorder. My psychiatrist has said to me several times that I am the only patient he has that is only ADHD. I have read many books and I love to read can’t get enough that says ADHD and bipolar have been misdiagnosed often. They mimic several signs of the same things. I hope you get all the answers you are looking for.