I would suggest that he buy a lunch for one of the people that he has been doing business with, and ask for an honest assessment of what skills they need, and where they see him as outdated.
Employers who have liked his work will probably be happy to help him move on. If they tell him that he needs one of the certifications mentioned before, he might ask if they would give him an "internship" (work for free, or nearly so) so that he could get an actual job on his resume. He would probably have to pay for the certification program himself, but solid work experience plus the certification is much better than the certification alone.
I'm suggesting a friendly lunch to talk about business opportunities, because that is often more comfortable for people who don't have good marketing skills (as you say this individual does not). It's less intimidating than asking the same questions in an office appointment.
What alternatives did he forgo when he first took the programming job? What are his passions? Put aside money and the security of the job. What does he want to DO? Answer these questions and the right job will reveal itself. He needs to look inside himself for what motivates him. He needs to find first the things that stimulate his interest. The job and the money will follow.
The best advise you can give your friend is to put aside the fear of the unknown and explore the known within. Only he knows what he really wants to do with his time. Sounds like he is being mislead by the fear of losing the security he once had. That is gone. But at 50, life has given him a portfolio of divers talents and interests that he could not catalogue in a week. And this no 25 year old can match. He has had decades in the work force to learn. Many of the skills he has learned he probably doesn't even recognize as marketable.
Tell your friend to take inventory. First of his desires and then of his skills. With this knowledge he will be able to find a place to deploy his talents