Perceived deficiency with Apple keyboards

Macs don't have an "overtype" mode, if that is what you mean, and they are persistently in the "insert" mode. I happen to agree with that choice because on PCs I only ever turn on overtype mode accidentally and usually become frustrated with it replacing my text but it's one of those Apple things where if you don't like it you have to adapt anyway or switch.

But in case you mean the ability to send an "insert" command that can be accomplished with the fn+enter on most Macs.

This document on Apple's support site may help you. You don't say which specific keyboard you have so scan down the page and click on the article specific to your keyboard.

http://support.apple.com/kb/HT1167

Just get a different keyboard. I have a Logitech Dinovo Edge and it's great.

That only helps if he's using a Apple keyboard to run Windows on Bootcamp by the way, in OSX there isn't an overtype mode and a different keyboard will not change that.

But I did think of one thing that might help him. Some software on Mac might implement overtype mode separately from the OS. E.g. Word on OSX at least used to (I haven't used Word on a Mac in ages) have a toggle for it at the bottom of the document (the OVR text) that when clicked on would toggle overtype mode vs insert mode.

Does that give you overtype mode when you use the insert key? Or does it just register as the Apple help key?