Welcome to qatar friend

Bankstatement is not needed for applying family visit visa. A six months bank statement is needed to apply for RP and i think engineers and above will only get RP and the salary should be 10000qr/month and the certificates should be attested by the embassy. i hope the link below will help you to apply for visit visa for your family.
http://www.gov.qa/wps/portal?New_WCM_Context=/wps/wcm/connect/cnt/en/1_H...