When does the 1-year ban for visa overstay in Thailand start?

The last day of his visa doesn't count. He is on overstay from the following day as day 1 so work 90 days from that. However its not a good idea to be on overstay at all so he should get himself to the airport ASAP with the required funds to pay the overstay fine, don't push it to the 90 days. If he is arrested on overstay its a much longer ban, even a 1 day overstay

hospitals give certification and even extend the Visa on behalf of patient

Why didnt he ask a medical certificate from the.hospital he stays in ? then his friend pass it to immigration ...

More than 90 days, 1 year ban. Entry stamp day counts as day one.

Hospitals usually have connections with immigration or ways to handle that kind of issue. Don’t wait any longer.

500 baht fine per day of overstay up to a maximum penalty of 20,000 baht. Blacklisting comes in at 90 days.

He needs to extend asap. The hospital should be able to assist with this.

He will have to pay a 20k baht fine on exit AND will be banned 1yr at 90 days.

If he were found by police on the street, for any reason, it's detention, deportation and min 5 yrs.

Hospitals have departments that help with these requirements.

It is too late for any medical extension relief.

If he gets a certificate from the Dr he can go to immigration and they have the ability to grant extensions based on the Dr prescription

Pro tip: you have to get the Dr to overstate the rehab timeline, instead of 30 days have the Dr prescribe 90 days to get a 30-45 day extension

Seeing that he didn’t get it prior to his overstay and you didn’t state weather he is staying full time in a hospital it will be tricky…if he’s in the icu etc then it will be easier

Talk to the hospital and his Dr

Sorry for the weird questions but may I ask what is the ban given for ?

Did he not get a certificate from the hospital to extend his stay on medical grounds?