No one reported seeing him for a couple months before his death, so I don't think he would have come into contact with anyone that he could pass a case of cholera from contaminated drinking water on to. He would have suffered alone. Those other illnesses you mentioned are possibilities as well. Denim being found sitting up in his tent with his eyes open makes me think of neurological conditions where people slowly lose their muscle strength and dexterity. Something like MS, Parkinson's, or ALS/Lou Gerhig's Disease, etc. Many illnesses could have allowed him to keep on hiking (but slowly) up until the last couple months of his life when he might go down hill. A friend of mine died from ALS and he chose not to go on a feeding tube for the end of his life. He had difficulty changing positions/moving on his own the last few months and would not lie down because he couldn't get up again without help. My friend essentially died from starvation due to not being able to chew food/swallow at the end. I also know several people with MS. My friends with MS can hide their symptoms on good days but when they have really bad days symptom-wise they need help from others for things such as zipping up zippers or lifting things. Even opening water bottles/tearing open a plastic bag of chips can be a challenge due to loss of dexterity and strength. If Denim had some neurological condition he might have eventually deteriorated to the point of being unable to open packaged food or get out of his tent. Sadly, there are so many diseases where starvation is the side effect that kills you if you don't have any help from others. MOO.[
It's unfortunate that the autopsy results haven't been made public in this situation. It's not like LE are trying to hold back essential information in the case of a homicide. It's appears the man died of natural causes. You would think releasing the results would only flesh out the profile of the individual so that family members of missing person may recognize them.
It's possible this individual knew he was dying or at the very least knew some serious physical ailment was affecting him through his extreme weight loss. Most people who experience that type of accelerated weight loss without any form of diet and exercise would go to the doctor to see what was happening. Cancer does that, especially bone marrow cancer. According to some of the people he spoke to, he had mentioned he'd undergone some radical weight loss. Heavy people who start losing weight for no apparent reason are initially ecstatic about the loss without realizing there may be some underlying reason and it takes a while before they decide to check it out. If he'd been given a serious diagnosis he may have been doing his bucket list. This is all supposition.
If it has been established he died of natural causes and not by misadventure (accidental poisoning, etc) I wonder why his autopsy results haven't been released?