Usually, a visit visa for your family gets issues within a couple of days if all your documents are in order. The visit visa is issued for only one month duration. To my knowledge, you cannot extend the visa by yourself if the visa is not utilized within the validity period. You may extend your visa up to six months after your family arrives in Qatar. For this, you will need to have the medical of your family done within one month of their landing and once this cleared, you will need to go the immigration office.
Usually, a visit visa for your family gets issues within a couple of days if all your documents are in order. The visit visa is issued for only one month duration. To my knowledge, you cannot extend the visa by yourself if the visa is not utilized within the validity period. You may extend your visa up to six months after your family arrives in Qatar. For this, you will need to have the medical of your family done within one month of their landing and once this cleared, you will need to go the immigration office.