I've been product managing and architecting for a years and now I'm out of work at age 52 with no obvious prospects for re-employment. I decided the developers were always having more fun than the managers. So I took my first course in c++ last month at a local community college (2nd quarter CS.... objects, linked lists, pointers, etc.). It was hard, but not impossible.
I have the same questions. Objectively, the idea of becoming a developer in your 50s is ridiculous, absurd, silly. But here's another thing that's even more ridiculous. - Getting up in the morning and having to do things that you don't give a damn about. So with my unemployment checks and savings I'm back to school to see how far I can go in the art of coding.
Will this enable me to support my family? I have serious doubts about it. On the other hand, it's not like there are other options falling out of the trees. It will take a least a year or two before I can even walk in the door and say "Hey I'm an old guy with some new skills... (and a lot of experience around software development)... what terms are you willing to hire me on?" If I do this thing, I'll do it the honest way, not pretending to be a 20 year old developer, and not asking for the salary of the experienced 50 year old project manager that I am.
Will it work? Will anyone bite? Hell if I know. But I do like playing with code, so I'm taking baby steps down that road and we'll see where it leads.