How immigration will treat you, depends on how long you overstayed.

If you overstayed 1 – 180 days, they will probably ignore the overstay, “no harm no foul”

If you overstayed 181 to 355 days, you are banned from applying for any new visa for 3 years from the time you left the USA.

If you overstayed over a year, you are banned from applying for any new visa for 10 years from the time you left the USA.

I hope that you overstayed less than six months.

First Homeland Security/FBI reviews your petition. This takes from 2 to 6 months.

Then they send the case to the consulate nearest to your Fiancee. Some consulates work faster than others. If he is in Philippines the process is very fast, with interviews arranged as fast as 3 to 5 weeks after Homeland Security approves. If he is in Vietnam it may be 2 to 4 months later.

Once he attends his interview the decision to grant the visa is made “on the spot”. If granted he gets his visa in a few days usually. Sometimes the consulate officer wishes to avoid confrontation, and does not tell denied applicants they are denied, instead telling them to come back later to obtain the results.