A friend of mine's boss has a 04 and it keeps blowing pump seals. He is putting in the fourth pump tomorrow, there from Auto Zone. I told him that's the problem, lol you would think one of them would hold.
Anyone had this problem?

Yes.  Which seals are blowing?  He can either get one from some other reputable source (rockauto.com migth be able to help with that), or try rebuilding the autozone unit with better seals.  Depending on which seals he's having problems with, it could very well be an easy job.

I have heard that some caps allow for over pressurization, but generally the lines blow off the cooler not the pump seals.

For curiosity's sake, what is he using for fluid?

2004 should be ATF fluid.

2004 should be ATF fluid.

Yes it should, but the number of pumps has me wondering.

When do the seals seem to fail, right at start up or after a few miles or after warmed up, certain driving conditions?

I think he's getting one or two months out of them. not running ATF might be the reason.

I've seen things like Lucas Steering additives blow hose and seals because it makes the fluid too thick in cold weather. Make sure to use the proper fluid and don't add additives to the fluid.

Due to the neglect most power steering systems receive I would reccommend a top quality synthetic ATF.