Note the citations at the end of the video (44:30 mark ). Code from some of the original research the spacex stuff was based on, adaptive wavelet collocation methods, used to be online in a bitbucket repo here: https://git.plgrid.pl/scm/tmh/wavelet-original-code.git
Unfortunately it seems to have been taken down. A shame - it was really everything! But as a huge CFD library research code it is a bit hard to sift through anyway.