I saw a post on facebook (sorry, lost the reference) where a player got disqualified due to a “miscommunication “ between coach and umpire. Is that within the rules? I think a coach can be asked to leave the immediate court area but can a player be disqualified from the match because of the coach remonstrating with the umpire? Bear in mind, officially, a coach by the court I think cannot talk directly to the umpire in a match.
Interesting. Assuming that this was a "BWF Sanctioned Tournament", in my opinion, this would not be within the rules. Though I'm not an expert by any means, the official code of conduct for coaches and educators states: "Any offence committed during a BWF Sanctioned Tournament can be penalized by the Tournament Referee, who may remove the Coach, team manager or team official from the playing area. The Referee may also in case of repeated offences during a Tournament or in case of serious offences (e.g. but not limited to clause 4.12) have the Coach, team manager or team official removed from the arena for the remainder of the Tournament or part thereof. The decision of the Referee is final and cannot be appealed." So like you said, the coach can be removed from the playing area, or even the arena in extreme cases, but the BWF rules don't appear to say anything about disqualifying the actual player or team, at least not that I've seen. Still, in tennis, players can absolutely be penalized, disqualified, or even suspended based on coach conduct, so I wouldn't be terribly surprised if there was a similar clause buried somewhere within the badminton rules and regulations.
Could you please find the original post? It could be still in your browser or mobile history. Alternatively, provide more particulars on situation, as in which tournament, what draw, which year, etc.