Tenant lost job due to covid 19 and did not receive rent for 7 months, can I deduct this?

Loss of rent is not deductible nor is there a tax credit available.   The resulting  loss, from reduced income and continuing expenses, should result in some tax savings. 

The last covid federal bill did provide some rental assistance.  Here's the info for Virginia.  A little internet search should find something similar for your state. 

The Virginia Rent Relief Program (RRP) is designed to support and ensure housing stability across the commonwealth during the coronavirus pandemic. Depending on availability of funds and household need, the RRP may provide financial assistance for rent payments for eligible households. This includes financial assistance for rent payments past due beginning April 1, 2020 and onward with opportunity for renewal based on availability of funding and the household's need for additional assistance and continued eligibility.

The $25 billion in rental assistance will be funded through the Coronavirus Relief Fund (CRF) and administered by the U.S. Department of the Treasury. Once the funds are dispersed to states, tenants will apply for aid through state or local relief organizations.

You can complete an online landlord-initiated application or check the status of your outstanding application at www.virginiahousing.com/RentRelief.

Tenants: reduced hours one of qualifiers

Is your current monthly gross household income (when multiplied by 12) less than or equal to $46,200.00?

https://www.cnbc.com/2020/12/21/stimulus-bill-includes-emergency-rental-relief-extends-eviction-ban.html