Fostering with an older person

Hi, we recieved our first placement and we went through our training and had an idea what to expect with a new child. However, our older member of our family didn't go through the training and is old school when it comes to parenting. This caused problems because they were stuck on 'respect' and because of that lost their compassion for our two foster children. Does anyone know or have any suggestions of how to get an older person to understand that a foster child may not be able to comply with rules and discipline if they never had them in their biological home? Also, how to get them to not to take their behavior personally.