Re: No respect
But what can we possibly say that isn't obvious? - I don't mean to minimize the distress this is causing but it isn't like there is a dojo police force or a dojo good fairy or good wizard we can summon up - plainly put, there is no "indirect" way to resolve this.
What are the possible outcomes to this scenario you describe?
Either he changes - unlikely -
or he leaves - which he will have to be told to do -
or the sensei leaves - possible but not what the students want
or a bunch of students get disgusted and leave - which really sucks
or things go on as they are - which also really sucks
So....if the sensei will not address the issue by asking him to leave or to shut up, then as near as I can tell the only other option is for the unhappy students to call for a dojo meeting and openly address the issue.
IMO the best outcome would be a split in which the disrespectful sempai takes off and any interested students go with him.