Mr. T: well, i have two separate views on your situation and they are both opposite! So as weird as it is i'm sending along both. Maybe one will feel more right to you over the other.
i think i have two opposite replies because i don't know your family history and how abusive the man has been to you. i also don't know if you have even an iota of loving feeling for him in your heart. So i guess each reply reflects those opposing possibilities.
i hope you will be ok with whatever you choose to do and feel good about it after.
Scenario One:Have those few drinks and stop in for just 1/2 hr. or so minimum. Be nothing but kind (the booze with make it doable).Make it clear in some diplomatic way that you are there to see him because he is so ill/before he passes so he knows its a one off.
You did your part to show up for a dying man at his request and you don't have to become re-involved with him or any extended family beyond the email you are already doing.
Also, don't give out any phone numbers or contact info. that they did not have prior to your visit.
Scenario Two:If you are dreading going there so much that you would need to numb yourself with a tranq. or booze, which who could blame you, then maybe you should not go.
When you go see someone who is dying it is supposed to be an extremely sacred time where loving things and feelings transpire emotionally.If you are going with it in mind to get out of there as soon as possible and in a numb state of mind to cover up feelings that are exactly the opposite, then ask yourself _why_ are you even going.
For appearances? To appease them? What i'm saying is that if there are no genuine loving feelings of wanting to be with or see your dad before he dies, then _why_ go through a whole charade??
You reap what you sow in life and if he was such a poor father to you then he has sowed this result at the end of his life. It's not vindictive or "bad" on your part at all. it is just how you feel, and this is rightful, after a lifetime of horrible, damaging treatment.
i say protect yourself. You can say whatever you want to say to your dad about the end of his life thru the same means as you have been doing already which is email.
i have this opinion only because if your dad is dying and you still want so much not to go see him at such a time then you really do have your answer wrapped up in your feeling.
if you want to go to start a fight like part of you may feel like, well i say don't go for that reason for sure. You'd probably feel worse after he passed then if you hadn't even gone at all, and you'd be hearing it from your family forever.
You might hear it from your family just from not going too, but i say that it is the time in your life to take care of _you_. if you feel anything caring at all in your heart for your dad still then maybe go in peace (with that drink or two... or 3 in you!) if you truly feel nothing- i wouldn't go for any kind of external reasons.
By the way in regards to being sick and not wanting to go, i'm just getting over the worst hell bronchitis and believe me when I tell you that feeling bad can last up to 3 months

But seriously stress makes it worse for sure and I was going thru stress that prolonged it and this stress about your family can prolong yours too.