"he believes he is entitled to his deposit. Is he right?"
Ever hear the old saying "people in hell want ice water too..but they don't get it?"
LEGALLY your tenant has a lease with you. It has a beginning date and an ending date. The tenant owes rent through the ENTIRE lease.
Your tenant is breaking his lease. However, he continues to owe rent until 1. a suitable replacement is found for him or 2. the lease would normally terminate.
It is unlikely that you will find a replacement tenant by September. Thus, his security deposit may be used for this months rent. I've attached the statute for your state that outlines what a tenants security deposit can be used for:
§ 42-51. Permitted uses of the deposit.
(a) Security deposits for residential dwelling units shall be permitted only for the following:
(1) The tenant's possible nonpayment of rent and costs for water or sewer services provided pursuant to G.S. 62-110(g) and electric service pursuant to G.S. 62-110(h).
(2) Damage to the premises, including damage to or destruction of smoke alarms or carbon monoxide alarms.
(3) Damages as the result of the nonfulfillment of the rental period, except where the tenant terminated the rental agreement under G.S. 42-45, G.S. 42-45.1, or because the tenant was forced to leave the property because of the landlord's violation of Article 2A of Chapter 42 of the General Statutes or was constructively evicted by the landlord's violation of G.S. 42-42(a).
(4) Any unpaid bills that become a lien against the demised property due to the tenant's occupancy.
(5) The costs of re-renting the premises after breach by the tenant, including any reasonable fees or commissions paid by the landlord to a licensed real estate broker to re-rent the premises.
(6) The costs of removal and storage of the tenant's property after a summary ejectment proceeding.
(7) Court costs.
(8) Any fee permitted by G.S. 42-46.
Keep in mind that you still have the obligation to notify your former tenant of the status of his security deposit within the required time frame for North Carolina.
Gail