Health insurance limits very low

Hello,

I appreciate any advice I can obtain on this matter. I am looking into health insurance options for my parents (ages 52 and 55). They live in New York City. My father has health insurance that covers him and my mother, through his employer, but the insurance is woefully inadequate. It has an annual benefit limit of $15,000. A simple proceedure would max that limit out immediately. I am concerned that they are highly underinsured.

As far I can tell, his current policy does not allow him to "tack on" any additional insurance. If he wishes to purchase an individual plan, he would have to cancel his employer sponsored policy. Are there any primary care health insurance plans out there that would allow him to increase his existing coverage, while holding onto his existing plan?

I have also been looking into supplemental insurance through companies like Aflac, but the payouts of their sickness indemnity plans do not seem very adequate either. Is this his only option if he decides to hold on to the employer sponsored plan?

Finally, what are the options if he does decide to cancel his employer sponsored plan and purchase individual health insurance? What are the best sites to use (keeping in mind this is in NYS, which has a very non-competitive health insurance market)?

Thank you very much.