How can I let a family member know we are each responsible for eachothers expenses w/o words?

well i can't see that you would get away with out having words about the subject sometimes its works better to have a conversation about each others responsibilitys your not supporting him or her they are responsible for those things them seles just say i have something to talk to you about and its related to your responsilbilitys as well as my responsibilities and then go to discuss each thing that needs to be discussed or you can write it out in a letter but that probably won't say it being talked about in person is better.