No, that phone is not with Sprint. (I'm on my Axim so I can't see what country he's from but I'm going to assume he's from the US).
The SE T630 is a GSM ONLY phone so it can be only used with GSM carriers and since it's a 900/1800/1900 tri-band phone that would mean that he's using T-Mobile unless he had it unlocked and in which case he could also be using AT&T/Cingular (I know my stuff and I know cell phones).
I will assume that he's using T-Mobile for simplicity's sake. There isn't anything wrong with you Axim, but there is something wrong with your setup. You need to first start trouble shooting with your phone and carrier. Make sure that you have paid for an internet plan that includes tethering. A lot of plans don't and just because you can get on the web and surf a couple of sites on you T630 doesn't mean you have full, unrestricted access to browse the web through your Axim, typically you have to pay a lot extra for that feature so check your paln or call up T-Mobile if in doubt.
Also have them send you an "OTA". An OTA is an "over the air" update of your phone's settings which could have been causing the problems. And while you're at it, talk directly to T-Mobile and ask them how to set your PPC up to access the net through your T630.
Good luck.
