[bpc9]

An interesting question. I haven't had to do any of this for my folks, but i'd probably do something like the following:

-Setup a network and computers that I can admin remotely. Probably Ubiquiti Unifi gear (great wifi APs, powerful router with DPI / firewall, where I have admin access from my Unifi Controller install. Then I could handle all network troubleshooting remotely, unless their ISP is down or hardware has physically failed (unlikely with the ubiquiti gear)

-Look at something like OpenDNS personal configured on the gateway to help protect against malicious stuff in browser

-Set up any Desktop PC to run a hypervisor, and keep the OS they use as a VM that I could access and administer remotely, and that I could quickly reset to a known-working state.

-Have them use gdrive / dropbox / onedrive to keep documents backed up and accessible across machines

-For laptop / portable, see if I could get them to use chromebooks, or I'd need to replicate the VM setup from the desktop PCs