Educate your MC or find a new one... Sending your H to a crappy MC is just doing more damage... You can disguise it as a parental training session... MWD even takes difficult cases like yours herself...
You need a MC that can EDUCATE your H, if his teacher is a fool you need to find a new FT who can do the job... It sounds like your H is willing to see a FT for parental reasons, so use that as the excuse... But I honeslty think you need to dump the MC if they aren't supporting marriage...
