I don't see when this article was published but it seems outdated. The team is using MEAP[1] which links to a wiki page listing technologies including YUI that are no longer maintened and was built on MonoCross[2] which doesn't appear to be maintained either. This was obviously a large endeavor to take on so I wonder how the team is dealing with this.
I worked on one of the largest Radiology SaaS coding/billing platform. Working with hospitals is one of the most strenuous industries. Everyone has their own formats and trying to learn the lingo takes a couple years.
Also many players have been in the industry for a long time and it's quite incestuous. I am no systems architect either but the validity of the data at any requested moment is very important so much of the services run in a synchronous environment. In my opinion as much as possible of accounting/scheduling should be async but this is one of the problems the industry is facing i guess.
[1] https://en.wikipedia.org/wiki/Mobile_enterprise_application_...
[2] http://monocross.net/