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Good morning, I am Lawyer Ak and I will be assisting you today.
You would be required to apply for adult dependent relative visa however you must be able to show your mother has long term medical factors she will require care for. Also provide bank statements to show you support her.
Is she coming to U.K. on medical grounds?
Then she will not qualify under this route as adult dependent visa but you may want to look at the Eu settlement scheme family permit.
It was a pleasure assisting you today.