Someone mentally unhinged enough to kill his own mother clearly is a danger to society though, unless there was a strong case that she deserved it. In that case, sure. No sense in putting him in physical harms way by putting him in jail.

Imprisonment as a punishment is a horrendously barbaric concept, particularly considering the current state of the American prison system. White collar criminals, or any color collar, if not a physical danger to society, should never be sent into those hellholes.

Prisons should be used solely for isolation. People like Charles Manson clearly need to be detained. Treatment, where deemed possible and necessary, should be done in proper medical facilities. People who don't need treatment and are not a danger to society should be in neither.

If their crimes are financial, punish them financially. Strip them of their assets and garnish their wages. It works for deadbeat parents (who I absolutely oppose putting into prisons).