My brother has an employment uae visa . He had...

It should be noted that after reviewing your inquiry and legal scrutiny we would like to provide you that the rule is that an expatriate resident who has a valid UAE visa and want to travel abroad for any reason, he should not stay outside the UAE for more than six months, and otherwise his residence visa will be invalidated. At this situation, he will only be able to enter the UAE after applying for a new entry permit or active the reactivation service for sponsors who have been out of the UAE for more than six months.
However, there are some exceptions to this rule, which allows the resident expatriate to remain outside the UAE for more than six months, while maintaining the validity of his residence visa in the country:

• The foreign wife who is sponsored by her UAE husband
  • A resident expatriate who works in a government agency, and his accompaniment, and he is sent abroad for treatment by the government administration. In this case, a medical certified report must be submitted by the Ministry of Health and Community Protection.
• Domestic labor who accompany who accompanying the members of diplomatic missions and consulates that representing the UAE abroad, and staff of these missions who hold a residence visa in the UAE
• Public sector employees who are sent by the Authority to attend training or specialized courses or those who working in the offices of employers abroad and their families who hold valid residency visas in the UAE
  • A student who residing in the UAE and travels abroad to study at a university (according to the General Directorate of Residency and Foreigners Affairs in Dubai). Check it out in other Emirates.

I hope my answer was helpful, please let me know if you have any follow up questions.