From experience go to the local ampur and police station. Make up an declaration that the husband left, without taking care and without answering. It will take one year after this and then she can get a divorce from the judge without him. In our village in the Isaan the first statement was filed with the police.
If you leave the country and you reenter, you have to report yourself in 24 hours at immigration with the "housmaster statement". Nothing to do with the 90 days
wow ... the last ... so you come 15 days to early .. you had only 75 days and then for the next time 90 days again. So if you come every time 15 days early you have to go a little bit more often then 4 x a year. If you come one week later you not "win" one week. They take the date you should have come.