An exception for the cancellation of an insurance policy is non-payment due to a covered condition such as Alzheimer's. Some companies will even ask you for a third party to notify in case of non-payment of premium. Most insurance companies will ask you questions concerning your health prior to selling you an insurance policy. A general rule of thumb is the more questions that an insurance company asks you now, the fewer problems you are likely to run into in the future when you are trying to collect a claim. The insurance company may contact your doctor or even health insurance company concerning your prior health.
Some companies require a waiting period for any pre-existing conditions.
However, you should always fully disclose all of your medical conditions in order to prevent trouble later on. For people over the age of 80, some companies will only sell limited policies or will not sell policies at all to these people.