Please help me family situation !?

before i start my dad's not an alcoholic but i really need help on this !! my dad drinks its like always on the weekends and like 4 weeks ago wee spoke and he said im never going to drink again but you need to stop being cheeky so i was like ok and he stopped for3 or 4 weeks and started again and last week was his birthday hes old so cant say his age lol so what he done was went to this guys house his old pal that drinks and left me at my Nana's and put his phone off and then i phoned my brother and he said he phoned him to get him at the hospital and he fell and broke the bone of his eye in 3 places so he went to bed sobbed up then i asked why did he start drinking and he said please don't talk about it i regret it enough so he said hes finshed and cause it was friday yesterday he said he was away to his girl friends to get his phone and said he was waiting on a buss and that took 4 hours so he was lying and then today me and my friend was going to the pictures so i asked him and he said ill see because he has a car and a said a night time and he said no a done how are you planning on drinking earlier and he said yes i hate him its just lies lies and more lies im sick of him and im only young and like hes not a tramp but he will be soon if he keeps doing this hes been doing this for years and my nana always says shes finshed with him then always forgives him and so do i , i dontknow what do to what should i do i need him to stop drinking he wont taqlk to anyone or that but he does try to stop but he just cant stop forever and hes starting to make me like shite the way im feeling !!!!!!