This post made me happy, just to know that there are 70 year olds working in software at the IC level. The oldest I have seen in my companies is probably 60 max - and I found a correlation between older people working in tech, and working as a freelancer / contractor. Probably because they have built up an expertise in an area so they can, plus enjoying the flexibility when you are possibly less reliant on the money (older kids, etc.). I want to see more people this age in tech, doing the coding / ops!

As for advice - I am not sure! Just keep applying. Don't let the age be a factor for him, and then if it is a discrimination factor for employers then it is unfortunate but keep applying anyway. There are plenty of people who appreciate talent.