When EMT's arrived, Max had no pulse and was "unable to breathe".
I think you hit the nail on the head. He may have broken his neck.
I would have given this no thought, had I not researched suicide by hanging. I'm in the small minority, who believes RN's death was a suicide.
RN's death was by hanging. Most adult hangings are suicide, whereas child hangings are often an accident. Hangings are rarely a homicide, because it requires a victim to be unconscious or intoxicated to complete without a struggle, which would be detected by markings on the body revealed in an autopsy.
There are two types of hanging.
"Suspension" hanging is with a rope around the neck and kicking or stepping off a stationary device, such as a chair. Death is usually by asphyxiation.
"Drop" hanging is rare (1%), with a rope around the neck and "dropping" several feet, which causes the neck to snap. Unconsciousness and death are quick, cause of death is fractured vertibrae, or "broken neck".
If it is suicide, she may have chosen a method that mimicked the injuries suffered by Max. In fact, this may be where the chandelier comes into play. Max's shirt may have caught on the chandelier, causing him to drop with his shirt around his neck.
I noticed some conversation about choking, chloroform or other methods to subdue. Toxicology results would identify drugging or other means to knock her out, autopsy would reveal markings unusual to suicide by hanging. In "drop" suicide, rope markings around the neck are significantly different than other suffocations, and would be revealed in the autopsy.
The Coronado police chief has stated there's no findings of criminal activity, as of this point in the investigation. The autopsy is complete, but sealed until toxicology results are available. This may be an indication that the autopsy points to suicide, and explains the sister's public rebuttal that Rebecca's death was not a suicide.
"Naked" suicides may be symbolic.
"In severely depressed individuals, a naked suicide may be an expression of vulnerability, utter despair, desolation, and worthlessness."
It's also expresses "anger and vengeance". Wednesday morning Max was scheduled for an MRI. Why would she choose early Wednesday morning to hang herself, when Jonah would be agonizing over a hopeless prognosis? To cause him more pain, to retaliate for the pain he caused her?
If I had to guess, he either told her to stay away from the hospital (she told the kennel owner she had to be at the hospital with "her son"), or told her to get out of town. I just don't think Max's parents would be plotting a murder, less than 48 hours after his accident.
More "naked" suicide theories . . .
http://www.jaapl.org/cgi/content/full/36/2/240