We recommend sharing the inconvenience and sacrifice that comes from changing family routines so that the misophonic person is not triggered. The misophonic person did not choose this condition – it happened to them. It is a bit like having a family member confined to a wheel chair. It affects everyone, but the family works together to make accommodations. So if a child has misophonia, and the father is the only trigger person, then a variety of schedule changes are possible that excludes the possibility of having the father chewing in the presence of the misophonic child.
It is important to make the plan with the misophonic individual. That may be difficult for children, who may be unwilling to follow such a plan. That is a different matter, but a plan is needed, and then the parents can calmly follow the plan and encourage the child to do likewise. This is also true for husbands and wives. Make a plan, and realize that being triggered is not a choice. Although it is not easy, try to not take it personally.