It seems like it's just a part of aging, sadly. My dad was using computers at MIT back in the 60s before hardly anyone else had ever seen one. I had access to a computer at home my entire life even though the most basic monochrome green PC compatible was $10k in today's money [1], and I remember him using an acoustic coupler modem to connect to some network (a BBS?) at triple digit baud through the actual telephone handset, long before the World Wide Web even existed.
And yet now ... he barely does anything with computers besides play freemium mobile games on his phone. Doesn't email too much anymore, doesn't have online logins to just about anything (like his bank accounts), and can't handle basic debugging of tech issues anymore. I think people just give up at some point and stop trying to stay current with this stuff.