Those staying with in laws and with helper. How is their relationship? My mil is those traditional type and very hard to get along with. Previous helpers all left becos of her. My r/s with mil isn't that good either and will often quarrel becos of helper. We try not to communicate if possible. Trying to keep my sanity here.

It's difficult since your relationship with your MIL isn't on good terms in the first place, which makes it doubly hard when communicating on issues regarding the helper Since you hired the helper, the helper should listen to your instructions so she isn't obliged to listen to your MIL. The best solution is to move out, but if not, try to have a good discussion with your MIL. It's not healthy to be living in this tense atmosphere.