Moms just can't be "fair". It's not in their nature. As a rule, DH and I never relied on either set of parents for daycare, diapers, Christmas gifts, etc., unlike my sister and 2 of his siblings. We chose to set a better example for our kids in the hopes that they will never expect such from us. But as a mother, I can understand why your mother allows your brother's family to disrupt the plan...she is the designated peacekeeper. I doubt she views
DVC as hers and yours alone, but rather a family investment to be used by the whole family, regardless of who the investors are. Sharing the point contract is sticky in any situation(my DH knows I will never divorce him if it means splitting our points

but I feel your mother should allow your brother to use only her portion of the points if your brother insists on a 2-bedroom. If he would consider a 1-bedroom(or better yet, a studio) for his family, you could certainly allow that as a 1-time "gift" from you and Mom, but let him know it is a 1-time deal not to be repeated the next time Mom feels generous. Let HIM know what your monthly payment is, so maybe he will do the honorable thing without putting Mom in the middle. And if you are like me, and do nothing but smile and bear it, take heart that you are not alone, sister. Our original contract and 2 add-ons were purchased by me, with my husband's only contribution being his notorized signature. I took on extra work and gave up little luxuries to afford DVC, and so far, we have taken only HIS family to WDW with us, with the exception of my sister and nephew for a short trip. Now HE is planning to take his free-loading brother(who makes more $$ than us)and said brother's girlfriend with us on our next trip. The fool left me in charge of reservations...brother is in a studio! With the savings in points, I invited our good friends to stay in a studio the same week with their 2-year-old angel! (The very thought of his brother in that big tub at my expense was just more than I could bear!)Good luck working this out.