About disturbing the peace... 415PC
If I yell at the top of my lungs at 3am in the middle of the street, I am NOT disturbing anyone's peace... UNTIL someone asks me to stop and I continue to willfully disturb them. If nobody on my block cares, I can yell all I want.
Time of day does not matter. I used to work graveyard shift and slept in the day, if at 12:00 noon my neighbor is blasting music, I ask him to stop and he keeps rock'n out, he is disturbing my peace.
Dont confuse 415 of the PENAL CODE with some local city MUNICIPAL CODE that limits noise after a certain hour, like 10PM.
The main issue I see here is a (possible alcohol related) "medical emergency", your passed out buddy. Cops are not doctors, just because you say he's intoxicated means nothing... for all they know you were trying to kill him & he had been yelling for help.... plus you just don't know what the informant told the police dispatcher. Very often people call in and add the word "gun" or get way too excited thinking more drama gets the holstein there faster.
One question, was anyone under the legal drinking age?, or "appear" under age?.. when juveniles are involved the rules change bigtime.
You can be cuffed for the safety of the officers, and they are allowed to "detain" you for what the courts call a "reasonable amount of time"... which is generally 30 min.
Entering / searching your house, well, yes and no.
With a supine unconscious person, an open door, yelling AND a call for service... it'd be easy for them to justify whats called a "cursory search", a quick look around for more (passed out) people and or the source of the yelling. Had they found something, like narcotics, you might get arrested but have a great warrant-less search issue to bring up in court (called "the fruit of the poison tree")
If the door was shut, you could have easily told them to wank off.
I'm 99% sure your buddy was not arrested, but transported "for his safety" to the hosp... had the police "taken" him, they'd have to pay the bill.... its a dirty trick cops use to stick people with nasty MD bills.
In Cali, and other states, you can be arrested for public intoxication (647(f)PC), held for 4 to 6 hours and released (per: 894(b)(2)PC) WITH NO CHARGES being filed. It's a legal sober-up detention... but if he went to the hosp, this wasn't the case.