He probably applied for the initial 90 days Non O at the embassy at home before he entered TH, but it still makes no sense. And they could fix it with 2000 baht…
Normally you just show your passport and get stamped in. At the airports they want your boarding card as well.
For all tourist entries you formally are required to show an onward ticket within the days you’ll get stamped in for, at least som nights accommodation or an invitation to stay privately and cash equal to 20K baht. This is rarely checked in the immigration unless they’re looking for a reason to deny you because of excessive travel history. With your still quite clean history my best guess is that you’ll be fine only showing your passport.
Personally I think you should be fine with your plan. You’ve stayed in Thailand for a total of 110 days this year and you’ve also spent some days on a tourist visa last year. Objectively speaking you’re still a tourist and not someone trying to live or misusing tourist solutions for long term stay in Thailand.