I would like to know if and where you can watch the deleted Minecraft Let's Play episodes of Gronkh?
You can do this with a WayBack machine:
Navigate to archive.org and paste the link into the WayBackMachine's search window. Click the Search button. You will receive information about the lost or deleted YouTube video and may be able to download it again.
And if the corresponding video is not stored at Archive.org, what then?
Then you could still see if any viewer uploaded a re-upload of it. Otherwise, unfortunately, I can't help you. I don't think you can do more than that.
Thank you for the effort.
No problem. Always happy to help! If you have any further questions, please do not hesitate to write to me and I will give you a competent answer as soon as possible.