Why psychological accounts of personal identity can accept a brain death criterion and biological definition of death

Psychological accounts of personal identity claim that the human person is not identical to the human animal. Advocates of such accounts maintain that the definition and criterion of death for a human person should differ from the definition and criterion of death for a human animal. My contention is instead that psychological accounts of personal identity should have human persons dying deaths that are defined biologically, just like the deaths of human animals. Moreover, if brain death is the correct criterion for the death of a human animal, then it is also the correct criterion for the death of a human person. What the nonidentity of persons and animals requires is only that they have distinct criteria for ceasing to exist.