I know a guy who works for Square D who uses his iPad for email.
His answers are so short that he may as well not answer at all. It is sort of the equivalent of a grunt instead of actual speech, the way he uses a one-word answer to respond to complex questions in an email.
This guy's name is Rus Emerick, and he used to be my friend, until he bought an iPad. I'll be damned if I am going to allow someone to be rude to me just because they've got a fetish for Apple hardware.
If your friend can't type a long email response to you, maybe he just doesn't like you. I can type at about 50 WPM on a real keyboard which is pretty decent for someone who isn't a professional typist. On my iPad, I would guess I type at about 50% of that speed... 25WPM is still pretty fast compared to most people. So I would just guess that you're a douchebag and your ex-friend just doesn't want to communicate with you in a meaningful way.
You are always doing something marginal when the boss drops by your desk.