They might be able to get a 89 day extension after being here on an initial 90 svp. After that they will have to leave the country for a couple of days (5 preferrably) and maybe (only maybe) they may get an additional 90 days visa. Or, they might only give them a 30 day visa. Or they may say they have to leave for a minimum of 6 months. It can go any direction. I would hope they would be lenient but you can never tell.
The safest method, and the least trumatic, would be to leave them home where they are surrounded by their own people and not be subject to the whims of immigration officers who don't follow any set protocol so may allow or disallow as they happen to see fit at the time.
SOME PEOPLE TRY TO TURN BACK THEIR ODOMETERS. NOT ME. I WANT PEOPLE TO KNOW WHY I LOOK THIS WAY. I'VE TRAVELED A LONG WAY, AND SOME OF THE ROADS WEREN'T PAVED. ~ Will Rogers