I think max winter is red John.

Lorali stated that PJ and RJ are alike

Max winter is way too alike to PJ, he sits, acts, talks like PJ and he even wears a wedding ring but he's wife is dead like PJ
When we see red John with rosalind Parker we see how RJ sits, holding his cup of tea, like PJ and like Max Winter when PJ and he met for the first time.
Mac winter also gives PJ the gun that kills Timothy carter like he was planning to get Timothy carter killed so he wouldn't tell anyone about who red John is.