There is a lot of information here. A few comments & questions to have answered to try to help you organize the thoughts :
1) you say he has lost 40 pounds. I’m assuming this is because he has already had bariatric surgery, correct?Or is this weight loss prior to surgery?
2). There is the diagnosis of Ehlers Danlos Syndrome (EDS) which likely on one end of a spectrum of Hypermobility Spectrum Disorder (HSD). There are some specific tests for EDS, but often the only tests for HSD is clinical using history and the Beighton score. If he had a high Beighton score, he could have a HSD and tested negative for EDS.
3). What was the original injury?
4). Where does MALS (Medial Arcuate Ligament Syndrome) come into all this? Is he having pain with eating?