My wife has been receiving ss disability for a few years due to 2 bouts with cancer. We were married in 2008 and the people at social security told her to never file a joint return or her disability could be lost.

Is that so?

I do not see HOW filing a joint return would have ANY effect on her disability eligibility.

However, before you file, send an email to the Social Security Administration and ASK, so you have a written record for the response.

Since a disability is based on the medical injury or illness, and is not income based

But perhaps you need to visit with them for more info