I reply as somebody who only has one experience of this.  

Holding hands is such a wonderful thing to do.  When my Mum was in the same situation I held her hand a lot and really felt it was so right to do.  One day I got some gentle piano music and put the earphones near one side of her head - she turned very slightly towards it as if to hear it better.  I chatted to others in front of her as if she was part of the conversation.  People say that hearing goes last of all.  And I took breaks away from her bedside to walk and have a hot drink and a cry so that I felt stronger when I got back. Sometimes I watched television and talked to her about what was on - relating it to our shared life (this felt a little rude at first but it is less intense for a while).

Keep holding hands and be strong.  Know that you are helping a lot just by being there.

Hi,

I am so sorry.

From someone who has gone through the same thing with my Dad and my Mum, I am thinking of you.

Holding hands is good. Your Dad will know you are there with him and holding him. I used to hum a little song before I tried to talk, mainly about what had been up to and the family. You will find the strength from inside, your Dad is very proud of you and you are there with him.

Be strong and you are in my thoughts.

Thank you so much for posting.  I went to see dad today and it was a little easier.  It's quite a comfort knowing that holding his hand is enough, it doesn't seem like much but if it's a comfort to him then that's good.  Thank you for setting my mind at ease. Xx