Best friend being rude to a girl I'm friends with/interested in

Anyone who has followed my story know how I made friends with a man named Hayden who has autism and his younger sister Skyla who cares for him. Skyla is bisexual and me and her went on a couple dates(with Hayden included. He mainly played with Legos). My best friend doesn't like them even though they had never met. She was with me at the mall when Hayden was staring at us but turns out he was interested in my Lego shirt. She had called him slow... I thought if we all hung out she could get to know them. We were shopping together (FINALLY got my stimulus) and Hayden was being Hayden. While we were eating and Hayden was getting restless, Skyla gave him a tablet to watch Lego ninjago on. My bestie asked how old Hayden was and Skyla sad 25. The my bestie said "Must such having to raise a 25 year old man baby". Skyla obviously looked upset but she told my bestie that she loves him how he is. My bestie asked why their parents didn't take care if Hayden and Skype explained how their mom is trash and shes been caring for him since she was 14 and he was 18. I'm not gonna say everything she said because she was just so rude and I kept calling her out but the thing that made Skyla get up and leave upset was when she said " You put too much blame on your poor mother. Nobody wants to raise a retard." So glad Hayden had headphones in watching Lego ninja go and didn't here this. Skyla just got up and told Hayden they are leaving. I chased after her apologizing. She says its fine she just needs to go and got in her car and left. I went off on my friend and she said she's been here way longer than Skyla and its fucked up I'm taking her side. Ugh. I need to figure out how to make this up to Skyla and Hayden even though he didn't here it.

Edit: I did message my best friend and tell her not to talk to me until she gets it together. I really need to figure out how to make it up to Hayden and Skyla.