There's no need to feel guilty cookiegirl, although I do understand how you feel.
We all have our own paths to follow, for some of us it's not such a wobbly journey and we have an element of time available to enable us to share.
Even those among us who don't have that luxury will (and have and do) offer what we're good at. A listening ear and a shoulder to lean on.
So, rant away my dear and offload some of that anxiety.
I am sure that you will all do your best (and that is all you can do) to make dad as comfortable as can be during the closing chapters. You care and you're there, even if it isn't as often as you'd like it to be. I'm sure your dad appreciates that.
None of us are superhuman cookiegirl and can only do what we can