Documents attestation requirement for family visa

My husband is as branch head in muscat from 12 may, 14 in well known company of muscat . I want to know when he will be eligible for getting family visa? Which type  of document attestation required from Indian Embassy normal or apostille??  What document have to get attested from indian & oman embassy for children admission in oman. like birth certificate . school certificate or any other certificate are required?? Also marriage certificate is required?? I am Post graduate in Computer Science and having 9 years of official job experience as a personal staff of IAS , Punjab. Also have experience as lecturer Computer Science . Can I get job in Oman??? My mother in law is widow and dependent on us can she get visa?? What documents are required for her visa??