I think swinging from very permissive parenting (which is what you are doing now, giving lots of gifts, no requirement for chores, allowing son to rule the roost) to very harsh parenting is not likely to work here. Someone suggested not allowing them to have a proper bed but only a mattress on the floor- that's ludicrous and likely to get a massive kick back/him run away.
You say you have mental health issues, so everything is doubly hard for you. Can you get any support from anywhere to help you keep on a more even keel with regard to parenting? What is needed is to be very consistent, a few rules (e.g. no swearing, no hurting others, everyone does one chore each week) but not implemented harshly or aggressively.
I also agree the gender inbalance needs addressing. Your girls have as much right to have space as your boys- and it makes sense for both children to share and you to have a small room (if there are 3). If there are only two rooms, there's not much choice anyway, but your son having one room and the women having three sends out a very strong message he's the boss here and that is important to tackle.
I think you need support to implement a more consistent regime at home, not just making knee-jerk actions to put your son down. Yes, he was ungrateful, but he's been made that way and harsh over-reaction now won't solve that.