does "diagnosis" by a colleague constitute knowledge of disability

[dc32]

I'm trying to understand the various ways that the employer can know about a disability. I understand actual knowledge and constructive knowledge (sort of), but what about if a colleague suspects you have a condition which you actually do have and the condition is a disability? Does that also count as knowledge of the disability? If so, does the knowledge transfer to the employer?

What if the colleague lies and says you denied having the disability? Does that let him and the employer off the hook for knowledge of the disability?

Thanks.