Sure. Ask him what football team he supports, and get him the appropriate scarf.

Hi! As an Australian, I have no objection to receiving a scarf as a present. I'd accept it simply as a kind present, that is all. The problem is that if you send him a scarf, remember our Christmas is in the middle of summer. It also depends where your friend is: I come from the south east corner of Queensland, and even in mid-winter (June-July) it's never cold enough for a scarf. Perhaps it would be fine for Melbourne or Sydney. If he's in a cold climate (eg. where you are now), then a scarf would be fine.

If your friend comes to China from Australia, he/she must be an Australian and i don't think Australian wear scarf, actually i'm not sure about that but you can give scarf as a gift though, if i were you i would like to give him/her a English to Chinese translation dictionary, so that he/she can be able to have fun more than he/she expected.

Of course! But it's probably better to ask him where exactly he comes from in Australia. Because if he comes from Northern Territory or On the top of Queensland(or Western Australia), he unlikely wears scarf in this life... those places are very very hot all year around. Have a lovely Christmas holiday with your friend!

It is perfectly OK.