"There isn't much time left"

The finiteness is real and I'm not going to pretend it away. There will be a last visit, and you won't know it was the last when it happens, and the guilt uses that hard fact as its strongest argument. Every Sunday you didn't go is a Sunday you'll never get back.

But look at what the argument does to the visits it produces. It makes each one a payment against a total you can't know, so none of them can ever be enough, and it puts the ending of the parent inside every ordinary afternoon, so you're never with her, you're with the idea of losing her. Penance under a deadline is the most exhausting form of penance, and the least present, and the least likely to produce the visits you'd actually want to remember.

Here's the alternative reading, and it's mine. The time being finite is the reason to give it whole, not the reason to give it all. If there are a hundred afternoons left, and you can't know that, then a hundred afternoons where you were there, unhurried, for an hour you chose, are worth more than three hundred where you were watching the cooker clock and hating yourself. The number of afternoons is not the thing you'll keep. The afternoons are.

And the last visit, when it comes, will not be the one that clears the debt. No visit can. The last visit will be a visit, like the others, and what you'll have afterwards is not a total but the visits themselves, the ones where you were there. That's what "there isn't much time left" is actually telling you, if you take the guilt out of it. Not go more. Go properly, and stop measuring.