Provide tax return to new owner?

I have been preparing an S-corporation tax return for a client who owns a small restaurant. She sold this S-corporation to her brother. Her brother's tax preparer claims that she must provide all the prior year's S-corporation tax returns to her brother because the tax return is owned by the corporation. Is this true? Thank you for any help or guidance.

Happy family.
If brother bought stock, then yes everything the corp owns is now his.
If brother bought the assets, presumably the agreement included books, accounting and tax records; so yes again.

Yep, what did he buy, exactly? See the agreement.

I'd send the returns to the former owner and ask them to share with the new owner.
Get yourself out of the middle of the situation.

Why doesn't she want to provide?

Thank you everyone very much for your help.

I'm unsure why she does not want to provide. He was an employee of the restaurant for many years. I think there are family issues because she sold it to him right before COVID-19 and now the business is not doing well.

I really dislike clients who hide behind our back in times of problem and pushes us to deal with their mess or complications. These are the clients that I would politely show them the door when the next tax season comes.

I'd send the returns to the former owner and ask them to share with the new owner. Get yourself out of the middle of the situation.

This is the best answer.

I agree, look at the agreement to determine if it was a stock or asset sale.

If it's a stock sale, any shareholder has the right to review income tax returns. The corporation can deny the request if there is no legitimate purpose for the request, but if the brother now owns 100% it's pretty unlikely the corp would deny the request since the brother is probably sending the request to himself.

I assume this was a bit of a handshake deal, so no transition agreement or anything like that and the brother paid the purchase price all up front?

You could consider asking the brother to work it out with the sister.