By Mark Weintraub ( January 22, 2018, 8:25 AM EST) -- When children plan for the care of their elderly parents, promises are often made among family members. From time to time, the promises involve one sibling giving up part of their inheritance in exchange for the other caring for their aging parents. These promises often involve ambiguous terms, or are not properly documented and are therefore unenforceable since they do not constitute binding agreements....