Has anyone ever gotten physical custody switch?

My husband has a 60/40 split with his son, 60 being with his mom, we have him every other weekend friday to monday and every wed morning to thursday morning, shared holidays. We have many issues with her on and off, it really depends on her mood, over the past 2 years shes yelled at my husband in front of the child and called him names twice, lets her family disrespect him ( son would tell dad what certain people of her family calls him /'stupid/'), and 3 different occassions his grandmother would ask him why he was leaving and "i thought you didnt want to go to your dad?", his mom recently moved back with her parents so now the grandmother is trying to take control and tells me i need to have the same clothes on him when she picks him up, my step sons mom scheduled her vacations days based on taking our days (allowed 4 weeks a year) and 3 different occaissions we dont see him up to 3 weeks. She doesnt allow him to acknowlegde me as his step mother, (hes only 5, but very smart) he knows who his mom is and the difference between me and her. When his dad calls him she tells thier son to not take forever, and you can hear her in the background making jokes about him. One time she kept hanging up on him mid conversation. Everytime we call she always has him front of a video game and lets him continue playing while we are TRYING to talk to him. She does not communicate school events, we know when they are but she does not let us know if they will be going and will ignore the call until the event is over. We teach him to respect all people of his family but her side is different, they find it funny when he has outbursts, 5 yr old talks like a baby when he is around them. Is there anything about best interest of a child with a parent that will support the relationship of the other parent and not try to "win over" his attention, We want to parent together but it doesnt help if she wants to do everything her way. Also the mother use to live closer and we agreed to have him attend the same school he started preschool, She even already filled out the paperwork and turned it in so he is already registered but since she moved back with her mom she wants him to attend by their house, he will be playing sports by my house in fall and would be very conveinient to not go back and forth 25 min each. i do not agree with taking him out 1 week after school starts, we do have joint custody but what do i do if she moved? i still want him to continue to go to the school WE agreed on. Sorry i started my question but i have many