yes it is possible to get misdiagnosed. that said since this is about your mother not you, there may be somethings that your moms treatment providers and your mom have discussed that you dont know about. diagnosing someone is more than just what family sees and knows about.

example a family friend kindly told me they thought I had autism and I should be on medication for autism.

I smiled and said well yes it may appear that I have autism but did you know that I have MS a physical health problem. I know someone else who has high blood pressure and has the same problems you are telling me are autism. I also know someone who is having the same problem of not showing emotions that you are diagnosing as autism. that person is pregnant and doesnt want her family to know yet so is purposely not showing her emotions...in other words completely normal.

this person (a family member who does know get to know my whole health history or attend sessions \appointments with my treatment providers) got the point... their trying to diagnose me with what ....they.... felt I had could very well have caused me a great deal of physical and mental harm.

my suggestion is go according to what ever your moms treatment providers say she has, they are the ones that have access to your mothers personal mental and physical health problems \ history and discussions with your mother.