What's your point?
I've been using IE at home with no issues. Telling someone to use chrome, which is also crap since firefox is by far the best browser anyway, is completely useless, you're not fixing the issue, you're bypassing it since you don't know how to fix it.
And back on topic
What i'm saying, I see you're in denmark, if you're using an english website or something then I assume you'll have different keyboard languages set up or something. If he puts the passwork into notepad he'll be able to verify what he's putting in, then he can copy/paste it into the password box.
If that fails, then it's something else.
Run this on his pc and post the log