Unless you plan to retire very early, you should try to learn guitar long before retirement. Learning something, especially music, is much harder when you get older.
I get that you’re trying to be helpful, but playing the guitar well isn’t the goal. It’s ok that it is more difficult to learn as you get older, the point is to enjoy the learning. It’s unhelpful to discourage anyone at any stage of life from learning to play a new instrument or learn a new skill. Enjoy the process when you are free to take all the time you need.
I agree. I have taught myself to play many instruments in my life. I can’t play any of them well, but that wasn’t the point. The point was to learn how to play a new musical instrument. Sure, I can’t pick up a saxophone right now and sound like John Coltrane, but I know all the essentials of how to play a saxophone, and if I spent a couple of weeks at it, I could probably do some basic, but listenable, jazz on it. With a guitar, I can’t pick it up and play like Jimi Hendrix, but I can play chords and sing along with them. I’ve learned a lot of other instruments at a very amateur level because the joy wasn’t in learning to play them well, it was in learning to play them.