My friend has a American passport and his 14 day entry stamp expires on 7th May which is a substitute public holiday. He was planning to get a 7 day extention before flying home

Does anyone know if the Imigration offic in Jomtein will be closed on 7 May?

If it is can he go the following day which will be 1 day overstay and still get a 7 day extention

Let your friend go on May 4 with his ticket.

They may extend his stay with 7 days counting from the 7th OR they just extend until he leaves the country.

Let him take THB 1,900, his passport and his ticket.