You might want to ask Shawn Yacavone, who owns Ukulele Friend (which owns the video channel in your link). Here's the link to the "Contact Us" page at the Ukulele Friend website.
That guy does an excellent version and plays it a bit faster, but listen to this one. He is playing it through on three different Martin ukes. The third one starts at 2:17 and is slightly faster than the first two. https://www.youtube.com/watch?v=CAcIGmVMTMs
I wrote to Imua Garcia and he told me the name of the song, it is a hawaiian song called "Kamehameha waltz".
It is almost impossible to find a uke tab for this song, so i made my own tab watching the video, now i can play and enjoy the song.