Chocolatetruffle ~
Jan is basically correct on both questions.
Question 1. To prevent any lapse of insurance and to continue treatment, is COBRA the only alternative?
The only feasible alternative, yes. Obtaining private health insurance post-AN diagnosis and/or while under treatment would be almost impossible and even if possible, the monthly premium would probably be more than your mortgage payment.
Question 2. Can the company lay you off knowing that you have a ongoing treatment?
Yes, but not simply for undergoing treatment, unless the treatment makes you unable to perform the job you were hired to do. In most cases involving an AN, this is usually arguable. No job is guaranteed and an employer can always lay off a worker for cause, be it lack of work, poor employee performance or something else, but the reason has to be verifiable and not malicious or without any basis in fact. Most employers can find a 'legal' reason to fire any employee. A string of subjective, negative performance reviews is a common ploy employers use to justify firing an unwanted employee. Re-shuffling job requirements is another. i.e. a 4-year degree was the original requirement for your position, now, the same job suddenly requires a masters degree. The boss says,: "Sorry, you are no longer qualified for the position. Nice working with you". Frankly, the way the laws are written, the employer usually has the upper hand - although there are many ways to appeal a layoff. Unfortunately, none are easy, quick, cheap or carry any assurance of success. The harsh reality is that with the shaky U.S. economy, lay-offs are going to be more common and totally justified, even for those undergoing treatment for an acoustic neuroma.
Jim