If you have PR it is better then DTV. For DTV they will change it soon and the officers are not happy with people who applied for DTV as I saw by my self and my friends told me.
You should tell him i will stay in Thailand 2 months, not more than that because some officers in the immigration will start thinking why he wants stay more than 2 months? Even u have Long visa there, and try to answer that u will visit ur country after any trip, the immigration can decide whether let u in or reject for small reason
i am in Malaysia, most of the countries are free entry visa, just some times they will ask for hotel and flight ticket going back, it depends on the officer in the counter, but for visa is free in arrival for US passport 30 days
Actually different country different rules in Thai embassy, same in Thai embassy in Malaysia they asked me to have visa in Malaysia for 5 years before i apply to DTV, they tried to bring new rules not available in different countries.