I guess the question becomes whether the presence of an open garage or unlocked door is evidence of a crime or emergency. I can't imagine how, on their own, either would imply an emergency. I know people who routinely leave their garage doors open (say, for family members who arrive home late at night and don't want to wake up the whole house with the sound of the garage door). I know people who leave their front doors unlocked, either deliberately or accidentally.
It even sounds like the police officers encountered some children immediately after entering the house, who no doubt told the officers that nothing was wrong. You might be able to stretch and claim the initial entry was justified, but you clearly cannot justify the officers walking upstairs, into the man's bedroom, to wake him up, after being told by the residents that nothing was amiss.
Hang these police ossifers out to dry.
