Is my Dad depressed?

I am sixteen years old. My father is 55 years old and he has been in a wheelchair for 38 years. He has been married to my mom for over thirty years, but I guess their divorce was ten years in the making. My mother claims he steals her medications. He sleeps too much, and when he is not asleep he is sitting a lay-z-boy watching tv for hours on end. He also became a heavy whiskey drinker and my family finds bottles all over the place. He used to keep our yard looking the best. He used to be out in his shed building and fixing things. But now we have to sell our house and its going to be hard finding another one because we built this one especially so he could get around easily. He got demoted from his job because he slept too much and never got to work on time and always left early. He forgets things too. He has forgotten to pick me up from school multiple times and take me to doctors appointments. He has also given up on his family. My mother used to have to remind my dad to call all nine of his siblings on their birthdays or call my grandpa to wish him merry christmas or happy fathers day. My aunt and uncle used to visit us all the time, but my dad was rude to them so they stopped coming over. All of our families friends have stopped coming over. I just want to help my dad.