This is a great space to be in. Contrary to even the tone of the article, mainframes are still widely in use across a huge number of industries. Typically in industries slow to adopt major changes - but we're at a moment where the COBOL skill shortage combined with increasing hardware costs is starting to make these machines untenable for even the largest institutions with the most inertia.
Having watched the video this seems like something one could achieve with GNUCobol, mainframe modules ported to the hardware of your choice and using some frosting made of nodejs/<insert hype web tech>. Why don't I feel enthusiastic?