Also thinking out loud...
I started teaching my self to code w/ the intent of getting a coding job at age 38, and I got my first coding job at 40. Breaking into coding was brutal for me. I couldn't get taken seriously as a junior. I just had to keep grinding until I was good enough that someone would take me seriously as a mid-level.
The way I did that was go super deep on learning Ruby super well. Then I found a company that needed someone who was really good w/ Ruby. They were willing to overlook my lack of depth in other areas because I had a skill that was critical to them. After starting the job, I had to work super hard to brush up on junior & mid level skills just to do my job at a good enough or better level.
After less than two years, people started thinking I was actually better & more experienced than I was. I could talk a really good game because I had spent so much time learning while I was getting experience, and then I started getting taken seriously for senior level roles. People saw my physical age & just assumed I was more senior & experienced than I was, so being older was actually an advantage to being taken seriously.
After about 5 years of coding, I finally felt like my work life balance was somewhat normal. I could start having a life again, stop learning quite so hard, etc. Now I'm just a normal, boring senior software engineer making a median-ish USA salary.
So I guess I'd say if OP's dad's path would be similar to mine, I'd ask him if he really likes software enough to spend a couple years learning to code & finding a job, then grinding for a few years to get to normal, and then enjoy 5 years of being a competent team member. It's certainly doable, but I think it's worth how bad one really wants this path. I think getting into software just for the money is not how I'd want to spend my 60s, but I'd absolutely do it if I found the coding enjoyable enough to self-teach & grind on learning for as long as it took.
It's also possible that other opportunities would open up just because of dad's knowledge of software. Just saying he likes to program, even if that's not his profession, could open up opportunities at a tech company doing other things, such as QA, support, scrum master, etc.