have been being – present perfect continuous – passive voice

Thanks to Carlos Julio Salazar for this question

Is this correct in English? –

My mum has been being treated by the same doctor for four years

The answer is yes, but it’s the kind of sentence that nobody would use in reality. It’s too long, too heavy. So what we should say instead? Using the present perfect simple seems perfectly fine to me:

My mum has been treated by the same doctor for four years

Because we have included the time, ‘for four years’ we understand that the action is not finished. If you really want to use the continuous, you should reformulate with another verb – “been being” just doesn’t sound right.

My mum has been receiving treatment from the same doctor for four years

Or why not use the active voice:
The same doctor has been treating my mum for four years

Conclusion: there are many things that might be correctly grammatically speaking, but they are necessarily the best way to communicate!