Regardless of whether he continues to run for POTUS, Biden should be forced out of being POTUS, he’s got no business being anywhere but at one of his mansions receiving private healthcare to live out his few remaining years in comfort and being taken care of in private.
Kamala Harris would be an unmitigated disaster but at least she is not suffering from dementia, she should be POTUS until this issue is resolved in November.
Based on your own premise, Biden shouldn’t run either.