People muddled by in a time before the Monkees (mom SN inventor) - in this case there seems little hope for a muddle that doesn't turn into a meltdown and dependence on 'Mother's Little Helper'.
On one hand, it's good that the fella is thinking ahead about parts of parenthood that might be challenging. On the other, uh, that's not one of the big difficulties....
If you witness a competent, healthy person struggle to put things on a calendar, what would your impression be? That this person needs professional help