One or the other, not both. It's my understanding, you can use the money in the bank throughout the year, but need to have 800,000 baht in the bank again, three months before you renew. You must also check in with immigration every 90 days. I'm no expert and not yet living there, but that what was explained to me.
Somewhat unrelated, I took a trip to Honduras several years ago with only 2 months on my passport and immigration in the US said they would let me go, but don't be surprised if they don't permit you into the Country. Honduras immigration didn't give it a second look. I guess your friend would be taking his chances. I think the biggest hurdle would be getting past the departing flight immigration, as long as the passport had sufficient time before the returning flight, you would probably be ok in the host country.
If it was me and I had time, I would opt for a new passport. Why take the chance if you don't need to?