It does now. The 2019 and 2021 updates make it clear that the survivor on a gay marriage or domestic partnership my inherit the benefits of a FHA reverse mortgage.
Because gay marriage was not validated by the Supreme Court until 2015, the survivor of a gay relationship who were not formally married or who had not entered into a formal domestic partnership can inherit the benefits of a reverse mortgage. This would benefit the couple where the two were residing in a state that did not recognize same sex marriages or registered domestic relationships at the time that one of the two took out the reverse mortgage.
Now that same sex marriage is legal nationwide, LGBTQ couples taking out reverse mortgages must be married or must be part of a registered domestic partnership in order for the survivor to inherit the benefits of the reverse mortgage.