I am the only person with a credit card unfortunately! We were hoping to contribute to the joint savings account with the goal of buying rental property one day

My mother pays almost $2.8k for the mortgage and can’t contribute a lot to this unexpected expense. My family member receives retirement funds and pays for some of the utilities every month. My brother works some hours per week and cannot afford to contribute. (sorry for any weird wording here. I am still building my finance vocab)