Section 7. If a patient at either of such Homes is discharged therefrom or dies therein while obligated to the commonwealth for support furnished him at such Home and there is in the custody of the superintendent of such Home a bank book representing a deposit account in a bank, as defined in section one of chapter one hundred and sixty-seven, in his name, which is unclaimed during the two-year period following the date of the discharge or death of such patient, the chairman of the board of trustees of such Home may present said bank book to such bank accompanied by an affidavit stating (1) the name of said former patient, (2) the date of admission of said patient to the Home and the date of his discharge therefrom, or his death therein, (3) the amount of money for which the said patient or his estate is obligated to the commonwealth, (4) that said bank book belongs to said patient or his estate, (5) that it has been in the custody of the superintendent and has been unclaimed for more than two years, and demanding payment of all or such portion of the amount represented by said bank book as is not in excess of the amount due to the commonwealth for the support furnished such patient.

Thereupon, such bank shall pay the trustees of such Home the amount so requested in said affidavit and shall endorse such payment upon such bank book, with specific reference to this section and shall return such bank book to such chairman.

Upon receipt of such payment the trustees of such Home shall cause the same to be deposited in its legacy fund or legacy account.

Payment to the board of trustees of such Home, under the provisions of this section, shall discharge the bank of liability to the owner of said property, or any person claiming under him, to the extent of such payments.

Any person claiming an interest in property surrendered to the chairman of the board of trustees of such Home, pursuant to the provisions of this section, and who claims (1) that said property is or was not beneficially owned by said patient, or (2) that said patient is or was not obligated to the commonwealth for support, as set forth in said affidavit, may within seven years following the date upon which such property is surrendered to the trustees, establish such claim by a petition to the probate court which, after determining the merits of the claim, may direct the trustees to pay the whole or any part of the sum claimed to the claimant.