Gmail variant used for income tax registration

[neku]

I had an old gmail account opened more than 15 years ago, now someone is using a variation of the email id with a . in the first part for his income tax registration. Hence due to gmails forwarding I am receiving all his emails from the income tax department , the information does not remain confidential. Should I inform the person to use some other gmail id without a . in the first part, for receiving his emails or keep receiving the emails of a person I do not know at all?