WOAH!!! The swearing MUST stop. PERIOD.
If he cannot talk to you or anyone else in a respectful tone, then he can go to his room until he talk respectfully.
Dad will HAVE to spend one-on-one time with his son. PERIOD. You will have to adjust to that. He only gets 2 days a week with him. Now, he has to share it with FOUR other people. THIS SUCKS! Put yourself in HIS shoes. Not only do your girls get FIVE, count 'em FIVE days a week with him - but NOW HE HAS TO SHARE HIM with them too.
Maybe you can have Jesse over one night during the week while the girls are with their biological dad and do something special with just him. I can see his side - although I've never experienced it - but he only gets to see his dad two days a week and has to share him. That's GOT TO BE HARD on a boy.
Take your girls out for a few hours so they can have some alone time.
However the swearing and disrespectful attitude MUST stop from EVERYONE - not just him. You said your girls are not perfect either. So ground rules MUST be set. If don't put them in place, things will get even more out of control.
Make sure EVERYONE is treated the same way - no preferential treatment for a girl or a boy. Same consequences for the same behavior.
Everyone has to make this work. You all have to give something up and negotiate what will make everyone happy - whether or not you need to set up a family meeting to discuss what everyone wants and needs and go from there - but to make it work, everyone has to be on board.
Best regards,
Cheryl