What should my South African friend expect when crossing from Malaysia into Thailand regarding entry duration and required documents?

Information please: I have a friend from South Africa... He will be crossing the land border from Malaysia into Thailand. I'm trying to help him understand what to expect. He only has one entry into Thailand before without a visa 2 years ago. Main question - Will he get 30 days on a Visa on Arrival or Exemption Entry (is it 30 days and which is it? VOA or Exemption. Also I read here of 'proofs' - in this respect what will he need?

Another question: if he needs proof of a return flight or outbound I have heard about airtickets that can be canceled with no penalty - any examples of those. And since he does not have a printer will a phone or tablet screen showing of a ticket be okay?