Historically, consular offices have been hesitant to issue back to back METVs and even if they do get another, immigration will become increasingly less likely to allow them in without scrutiny.

If they do get another METV I’d be sure they have 20k baht (can be in other currencies as well) in cash and physically on them, a confirmed flight out at or before the 60 day mark (the 30 day extension is technically not guaranteed) and proof of accommodation (ideally a hotel booking). With those they should be able to satisfy the sort of easy things immigration go to when they want to deny entry but if an immigration officer really doesn’t want to let someone in they’ll find something else.