Can you please also elaborate on what you mean by "can't install it". Does it not show on the Playstore for him or is he getting an error when installing it etc?
What are your thoughts about this forum? Let us know by doing this shortsurvey.
The government of Gambia has blocked Viber. The below URL provides the details of the same and also is giving an option of an alternate app that you can use to connect with your loved ones. Enjoy..