From the Ethicist:
There are two distinct arguments for encouraging your children to visit their father. One is that it would be kind to him. Kindness is a virtue, of course, and it is especially apt when directed toward people to whom we have a debt of gratitude. Whatever else he did, their father did help bring them into the world, and it sounds as though they have good lives. So they may have reason to be grateful for that. (True, reasons for gratitude could be swamped by reasons for resentment.)
The second argument is the one you’re emphasizing: regret prevention. Were their father to die while they’ve severed ties, they may be sorry for what they weren’t able to say or hear. If they were to discuss with him why they have kept away, for example, he might have the opportunity to acknowledge some of his failings as a father. Unresolved conflicts with the dead can be burdensome. So your position is a plausible one.
Now, when your younger child says, “I’m not ready,” it could mean, simply, “I don’t want to see him,” which is a decision an adult child is obviously entitled to make. Then again, it could mean, “I want to see him, but not yet.” That makes sense as a feeling, but if it’s predicated on the father’s remaining alive and somewhat lucid, it might not make sense as a plan.
Dealing with family members who are in decline is easier when you have a happy history of engagement with them when they were younger. For one thing, you can distinguish new problems from their longer-term character traits. For another, you can think of the challenges of dealing with them as part of a package that includes pleasanter moments. Your children may have no such history to draw on and no fondness for their father’s longer-term traits. Even so, you don’t seem to think they would be unable to manage a little time with him, however uncomfortable.
So, without pressing too hard, why not have another go? Tell your children plainly why you would like them to consider visiting their ailing father. To your younger child in particular, you can say that you’re not asking anyone to feel ready, only to recognize that it’s impossible to know how much time this man has left. They may remain unmoved. Fair enough. You’ll still have done something a loving parent does: pointed out an option that you think your kids haven’t taken seriously enough.