Parapunter
IE7 needs at least XP, will not work on 98. Obviously IE8 has no chance of working on 98
Anything newer than Firefox 2.0? Same
Newer versions of Opera? Guess
Chrome? XP or later
So, you can see the problem. The more "modern" versions of the most popular browsers simply will not work on W98 so upgrading is probably the best way to go. Also, it will mean that K'n'C might have another 10 years of happy computing with a puter that will be more suited to the bloated software we use today.
Of course, he could go Linux but that's another story.