Declaring a particular person an unbeliever or hypocrite requires attention to the difference between outward evidence and inner reality, certainty and suspicion, and the relevant legal proof. Allah alone fully knows hearts.
Outward rulings relating to prayer and funerals for those who profess Islam are not set aside merely because of personal suspicion.
The sanctity of life is foundational, and unlawful killing is gravely forbidden. A person's emotional or self-appointed verdict does not replace religious and legal process.