[Vuejs]-Vuejs treeselect – conditional checkbox

I updated your code https://jsfiddle.net/fazanaka/cpvp989z/1/

Just need to add

isDisabled: true

If you are OK with c also being disabled (since it is a nested child of a), the docs say to use: isDisabled:true

https://vue-treeselect.js.org/#disable-item-selection