struggling to say goodbye

hi am new to these chat forums i.i m struggling to cope with my dads terminal cancer he has had it for two years though me and my brothers recently found out this march long story as my step mum hid it from us/ added the ultimate blow by telling me i cant say goodbye due to her own issues is all sorted now though i cant bring myself to face my dad  and say goodbye i m told i will regret this though i m going through one rollercoaster ride of emotions i just want my dad to be out of pain knowing hes struggling every day as he has stopped having chemo and has been told he has weeks left is heart breaking how do you cope with this any advice much appreciate thank you xx