Dividend received for shares not owned by me and Tax liability.

Dear Sir/Madam,

Here’s the matter.

I was second owner of a bank’s savings account. The first owner was my relative (No immediate legal heirs for that relative) . He was getting his shares dividend in that account. A few years ago, he expired. The joint account is now under my first and sole ownership. He did not nominate anyone on his demat account, so that demat account is still active.

I still receive shares dividend issued by companies to him in that savings account which is now under my PAN and ownership.

So I receive dividend for the shares not owned by me.

Is this entire dividend amount received in this fashion now to be considered Income from Other sources and being taxable?

Thanks and best regards.