What condition does Chuck suffer from in McGill brothers eventually develop into full-blown fissures and Chuck takes his own life as a direct result of their feud.
A defining characteristic of Chuck is the medical condition he purports to have: electromagnetic hypersensitivity. When viewers first meet Chuck, his house is stripped of modern appliances, guests are forced to remove any items on their person with a battery and Chuck is unable to be in the presence of excessive electricity. Exposure to electromagnetism sends Chuck into a dizzy haze and can cause him to black out entirely. Not only does Chuck largely avoid the outside world in Better Call Saul, but his strict medical requirements push others away from him, with the exception of Jimmy and fellow HHM partner Howard Hamlin.
Although Better Call Saul often presents Chuck as a kook, electromagnetic hypersensitivity is a genuine term, albeit not one that any medical organization would recognize as a genuine condition, since EHS has never been scientifically proven. Broadly speaking, the causes and symptoms of real-world EHS are the same as those Chuck experiences in Better Call Saul, but because the condition sits on the edge of pseudo-science they're are difficult to define. Triggers usually involve electricity in public spaces such as cellphone masts and generators but can extend to simple household appliances, similar to Chuck. Likewise, symptoms can vary all the way from mild headaches to losing consciousness, suggesting Chuck's EHS sits on the more extreme end of the spectrum.
Once again, there's no evidence to suggest certain individuals are more sensitive to electromagnetic fields than others, and if a patient visits a ed doctor claiming to suffer from EHS, the physician would explore all other possible causes for those symptoms, including the psychological route. This is reflected in Better Call Saul season 3, where Jimmy has a battery slipped into his brother's pocket in court to discredit him.
Further evidence that Chuck's problems are mental rather than physical comes when his condition begins to improve through therapy. Chuck uses grounding techniques (noticing and describing objects around him) that are taught to sufferers of anxiety, PTSD and various other psychological conditions. Conversely, Chuck's condition worsens during times of great stress, and was initially triggered following the breakdown of his marriage.
While Chuck's condition is real in the sense that EHS is inspired by real life, it's certainly not real in the traditional sense. Like anti-vaccination and climate change being a hoax, EHS is the result of false information spreading and seizing advantage of those with existing psychological conditions. EHS also plays upon the newness of modern technology, planting seeds of potential side effects without any evidence to back those claims up. Through Chuck, Better Call Saul accurately presents both how convinced a person can be about suffering EHS and how debilitating that can be, while clearly highlighting the mental causes behind the condition.
Better Call Saul season 6 has been green-lit by AMC.
Source: WHO