No, the 55 mins youll spend in thailand will count as one full day same as if youd entered 23 hours earlier. If its important wait until after midnight to go through passport control
If youre talking flights the chances nowadays since covid of getting the money back quickly is near zero maybe 3-6 months. Expedia are quite good but they have the airlines to deal with.You dont explain why you need refundable. If we know that, we may be able to give advice
If hes a thai national with his Thai ID card he should have medical cover at government hospital automatically i thought. Be careful not to fall for a scam here