This is interesting and maybe a good way to avoid the dynamic IP issue with helping your family out with their computer problems.

TinyApps.Org : Free and easy remote access (through firewalls and NAT routers) with VNC reverse connections

Long story short, take advantage of VNC’s listen mode. Connection would be made from Mom’s computer to YOUR dynamic DNS, which you could easily build into a batch file. And then you would be controlling Mom’s computer. It’s like a client/server in reverse. (Actually it’s kinda like how X/11 works.)