What you want to do is install a second dialler, on a pay as you go service so if you will only pay a few pence for the test. Installing a new dialler should not affect your AOL setting but would allow you to dial an alternative provider to test your speed.
It is possible for the more well equiped ISP's to detect heavy users and deliberately put them through a slow link, I have no idea what AOL do. But I seem to remember reading that they are heavy in to caching and use that to reduce their outgoing Internet bandwidth. So if you are a heavy user (on line a long time, as opposed to loads of downloads) you may think about an alternative provider.
Tiscali are a big provider with a generally unaobtrusive approach. They have pay as you go service which is free and gives all the usuals.
One thing to remember though, for all service providers the flat rate systems are different to PAYG, so there is no guarantee that switching will be any faster.
I'd get your friend to install a PAYG service from an alternative provider, if its significantly faster, think about moving.

Even if you get no uptake in speed, keep the alternative dialler, its good backup if AOL go down.

Hope I haven't blown you away.