Can health insurance companies drop a person if they get a major illness?

(Or raise their premiums so high that they cannot pay, which is basically the same thing.)
--------------------
The answer to that is an "Absolute" YES. For most health insurance companies and many HMO's this is a common practice. Some will even deny care due to a violation of their policy rules (ie. they will claim that you had a pre-existing condition that was not declared - even acne) and retroactively make you pay back what they for on a claim. The most common practice though is to increase the premiums to the point that you can no longer afford it or go bankrupt.
Source