Disclaimer: I don't approve ageism in tech, I'm merely trying to explain the reasoning of the other side of the negotiation table.
The unspoken truth about the job market is that the older you get, the more you should rely on your network when finding jobs. Simply maintain professional contact with 5-20 people that worked with you, know that you can deliver and would recommend you (citing the projects you successfully completed together), hire you directly, or at least give you a gig. Yes, it's a completely orthogonal skill to doing the actual job, but this is something that successful hires do.
So if a 65-year-old person files a cold-call application for a management position (that involves building professional relationships with your colleagues in order to make things succeed), it is very reasonable to ask what happened to their network and why nobody from the network would not have recommended them.
The article actually gives a hint when it mentions selling the assets and accumulating credit card debts. I'm sorry to say that, but this is an evidence of poor resource management. A good resource management strategy in this case would be:
1. Damn, I've lost my job. OK, I have X months on runway. Let's try to find another management position.
2. Oops, my runway is at 80% with no offers. I get 10% conversion ratio from applications to interviews and 0% from interviews to offers. Let's cut down expenses and try experimenting with what I do on the interviews.
3. Crap, runway is at 60%, still no offer. Let's kick down and try to find a dev position.
4. Runway is at 40%, no offer as a dev, still 100% cutoff after the interview. Let's try to apply for a remote position.
5. Runway is at 20%. Get a freakin' trade that people can realistically do in my age, secure recurring income, try to step up and find a remote dev job.
Nothing personal, but if you cannot manage that, you will likely not succeed at managing a multi-million dollar software project either.