I believe that you can.
I had a similar gripe when a company I used to work for passed out a "special dialer" for remote users to connect to the company vpn.
I didn't want any "special dialers" -- so I instead used the normal dial-up-networking configuration.
Somewhere in the properties or options is a check-box for using a terminal window. I think that's what you'll need.
When I did that, I would enter in my username@domain and password... It wasn't a task for the non-technically minded, so if your parents are as non-technical as mine it might be too complicated.
I'm guessing AOL probably has some wacky user-id and a long semi-encrypted password... (but I may be giving them too much credit). If your comfortable with trial and error, I'd suggest running a packet sniffer like "ethereal" and seeing what gets sent when you connect. Hopefully, you'll be able to see the username and password that the dialer sends (keeping in mind it may be semi-encrypted).
Then, using the terminal window with dial-up-networking, just type in the same stuff.
hope this helps