He can also take the LCC Air Arabia which operates A320 Kabul-Sharjah twice weekly Monday and Friday, I'm sure a much better option that the three you have mentioned.
www.airarabia.com
Other than that PIA (Pakistan International Airlines)also fly Kabul-Peshawar once a week with a 737-300 from where he can catch Emirates A330-200 to Dubai, they also fly thrice weekly Kabul-Islamabad 737 (one flight is via Peshawar) from where he can get on Emirates 777-200ER.
From Peshawar he can also fly Qatar Airways A300 or A320, Gulf Air A320, Gulf Traveller 767, Saudi Arabian 777.
From Islamabad British Airways 777 nonstop to LHR thrice weekly, Emirates 777, Saudi Arabian 777, Qatar Airways A300, Gulf Air A330, Gulf Travller 767, Kuwait Airways A320/321.