In-Law Drama with Newborn

My brother had a baby about 7 weeks ago. It’s the first grandchild in our immediate family and he lives about 4 hours away. My mom has been so excited and has spent alot of time preparing for the new baby (sewing newborn dresses, making a room in her house ready for a baby to visit, etc.) A week after the baby was born, my mom and I went to visit for one night and made the mistake of staying with them. They have a 3 bedroom 2 bathroom house but we definitely felt as though we had overstepped by not getting a hotel. We spent a majority of the day outside of the house and tried to stay out of the way. After we left, they told my mom she could only come back if she got a hotel room. She’s 64 and would be traveling alone. She’s requested to come visit and spend one night with them and they keep saying no. She has offered to stay with the baby while they go on a date night, cook meals, etc. I felt bad for my mom as she has been devastated about this and i called my brother to discuss. He told me that we are being completely disrespectful and that he shouldn’t be responsible for my mom’s well being while he’s trying to adjust to his new life has a parent. He said his wife’s family has respected his and his wife’s request to stay in a hotel without hesitation. I want to respect his bounderies but also feel like he should respect our mother to a certain extent. She doesn’t seem to be asking for much - just wants to drive up and spend one night with them. I don’t have children and he keeps telling me I don’t understand. But I do try to appease and respect both my parents and my husbands and have already thought about how I will try to let my own mother in law stay and visit whenever we do have children. My brother says its ridiculous that I’m taking my moms side over his. I just feel so bad for my mom. While I do think my mom is being a bit selfish, She is depressed in general and has struggled with her mental health for a long time. This baby was supposed to bring alot of happiness and joy into her life. Please help.