, well actually some airlines were asking for that ( read previous posts on this page) immigration will hardly ever question your ticket status..just going on experience 🙏🏿
Just phone them at airport and ask them if they’re wanting onward ticket or return ticket with the 30 days...if they do just book a cheap ticket from Bangkok to Cambodia within the 1 month....cost about 30 quid...really don’t worry it will be fine...
When he arrives at Bangkok, there’s no forms to fill or anything, just a 30 day stamp...