actually he did receive a warning, he was only stamped in for 45 days rather than the full 60 days. Chances of him getting back in on either a tourist visa or visa exempt are slim
You aren't blacklisted but you need to understand that you are at the limit of tourist or visa exempt entries. You'll be able to get the 30 day extension OK but if you want to come back after that you are going to have to get a visa that will allow you to do so
You will also need to cancel your work permit. You can do it all in advance with a letter from your employer otherwise you need to all leave Thailand on the day of cancellation. If you are able to work things between your old and new employer (they need to collaborate) it should be possible to cancel your existing extension of stay and immediately apply for a new extension of stay with your new employer