Is it normal my mum thinks she has every illness that a family member has?

Everytime if my family gets something wrong, such as diagnosed with a mental illness my mum will claim she also has it and to get over it and stop complaining. Now I know my mum does have bipolar, however currently she claims she also has anxiety, depression, diabetes, vertigo, borderline personality disorder, and autism.

The reason I think she is lying is because she will only claim she has it after a family member gets diagnosed, with no past claims of having the issue, only after it's revealed a family member has it.

I'll use an example, my sister recently went to the hospital and the doctors diagnosed her with vertigo, literally one week later my mum is telling us she also has vertigo, even though she has never told us that before.

She claims she also has anxiety even though I have never seen her have a panic attack, and isn't scared in public at all. I once had a panic attack while I was out with her at the shops and she started screaming at me, calling me retarded and a bitch.

I just want to know, why is she doing this? It makes me really dislike her, and I am very confused on why she is doing it