The Truth About Aging in the Tech Industry

I know it happens because I read about people not being able to be employed in their 50s. But it's not what is happening my experience.

I'm in my 50s. I'm a software engineer at a startup in Seattle. I work with people in their 50s, 40s, 30s, and 20s. I have a couple of friends in their 50s, they both just got jobs at amazon as software developers, before they had been in local Seattle companies like microsoft, google, facebook and many other smaller companies that I won't name so as not to out myself. I've also been through startups, big companies, dev and management roles going back and forth.

What does IT mean in this instance? A family member is also in his 50s, I worry that he could lose his jobs, he's on tech support (networking, server software stuff) at a big company but apparently still has confidence in his employeability.