Can my son with an Israeli passport re-enter Thailand through the Nong Khai border under the visa exemption program, and how long can he stay?

My son holds an Israeli passport and wishes to cross from Laos to Thailand through Nong Khai land border crossing under the visa exemption program.

During 2023 he entered Thailand twice. Once by land and once by air.

Will he be able to re-enter through the land border crossing?

If so, how many days will he be able to stay in Thailand under visa exemption? 15 or 30 days?

Thanks!