I think your friend have dry skin type thus facing such issue during winter. He can apply branded 'coconut hair oil' two or three hours before shower and massage scalp gently and take the shower later. He has to drink plenty of water and fruit juices to avoid it naturally. There are few do's and don'ts to be followed on this to become healthy and natural skin.
The second one is, he can use Henna (Mehandi) twice in a month to get rid out from itching on scalp. Again, it (Henna) has to be applied at least three hours before shower and wash with warm water gently. If he is usually traveling a lot and face dust then it may itch generally thus, he has to take care of it. The above tips are enough to get rid from itching scalp during winter.