I don't think I actually understand your comment correctly. Could you elaborate? There are many intelligent people who do great work in one area while failing in another. A successful entrepreneur who is into alternative medicine is not particularly surprising.
IQ, a single number, is important because people who are smart in one area tend on average to be smart in others. Jobs was extremely good at making decisions based on an intelligent analysis of complex information so I would expect him to be at least above average at making personal medical decisions.
Jobs has been described as
a polymath, a skilled motivator, a decisive judge...and a gifted strategist.
We should be shocked if he did an incompetent job of choosing his own cancer treatment.
First, Darwin describes Jobs's (far mode) stance towards death:
But these are Jobs's actual (near mode) actions regarding his own death:
The conclusion: