Need some Vuex code for a Vue/Quasar application

I have a parent Vue that injects a child page. On the parent page the end user can select a different member from a grid. When the member is changed a Vuex method is called to store the MemberID

this.$store.commit("memberInfo/setMemberID", arg["data"]["MemberID"]);

The child (injected page) retrieves the MemberID by

let memberID = this.$store.getters["memberInfo/memberID"];

on the vue created method. It works totally fine on the first load

I need some code that makes the child into a deep watcher so that when the enduser changes the Member on the parent page the child page sees that the MemberID has changed and changes the data on the page.

Please don't place an automatic bid and then chat and say you need to raise your bid it's not fair to others. Please bid what you think it is worth. I need this code right away so I cannot wait days.

I don't need a code just some instructions to what to do. I could post this on StackOverflow but I think I can get better results here