Sure hate to hear that. Family is hard to work with sometimes.
I had a rocky relationship with my father too. As a young child I sought his attention and time, it didn't usually end well and I tried less and less. He was an alcoholic, but he always held down good jobs and was talented to build, weld, or mechanic. He was very verbally abusive towards my mother and I and usually that was as far as it went. To other people he was a good hearted man that would drop what he was doing to help anybody out. There would be times that something didn't set well with him and others would see a glimpse of that side of him too. Both my mother and I shut down and tried to go along to keep things diffused. There were several examples of him trying to be helpful and generous towards me, but due to the other stuff I couldn't feel it was genuine even though in the moments it probably was.
I could never suit him when I was doing any work with him. I heard a lot of times that I couldn't do anything and would never amount to anything.
His health had been slowly declining from emphysema for several years and he is passed away when I was 18. He had been in the hospital for over a month around a year before. My mother told me one time that he couldn't understand why I didn't come with her to visit him more often. I went to see him the next day. I always wanted to have a good relationship with him. After he passed 29 years ago its been a real journey of coming to terms with what was and what could have been. My wife tells me that if he had lived to know me as an adult that things may have been different between us in time. I like to think so, but part of me has always figured it would be a similar story to what you are going through now.
For what it's worth the best times that I had with him were when I was in my mid teens and we would go somewhere with some of his friends. He always said that my mother sent me along so they wouldn't do nothing as he called it. I learned from some good cattlemen during those outings. It helped if there was that third party there.
My thoughts and prayers are with you
If you need to talk things through, myself or I'm sure several others here are available.