Hi in normal case 3 months is only provided but you can have a try out in Madinat kalifa MOI HQ where you need to meet the captain and explain him the reason so you can get 1 more month extended, Also i have come to know that if a person on family visit visa leave the country you can re-apply for a new visa the next day itself which i have double checked with Wakrah Immigration for my wife father in law. hope this helps you