We all have the right to be left alone if that is what we so choose. If a person enters my home announced or unannounced and I did not afford them entry, they will be shot. The notion that a cop can enter your home to check on you without a warrant is making the cop the intruder. I am sure that this cop should never have entered someone's home without other officers of the court present. I'm sure policy does not support what took place.
The cop didn’t take it unto himself to enter the home. He was asked by the man’s family to check up on him, which presumably gives him permission to enter the home if nobody answers the doorbell or knocking on the door.
That's a very good point. If this sort of thing is allowed to stand, then there's nothing to stop me from calling the cops at 1 AM and saying "I think I saw blackdog just leave a bar. He looked really depressed. I'm afraid he'll hurt himself of someone else."
Then at 1:30 blackdog's door gets knocked in. Unpleasantries result.