Firstly, the part of the house that is used for Airbnb is a joint asset unless he also considers your house to be his house and sees you as one of those Airbnb tenants. Therefore, the money you get from that is not his income. It's a joint income. Based on that "his" half in that is 15k.
If you both accepted that he wouldn't work after he gave up his job, then you both have to live the lifestyle that the lowest paid person in the household can contribute to. In his case, that's based on whatever contribution he can make from "his income" of 15k.
Secondly, this situation requires an open and honest discussion about the state of your finances, the debts etc. Before you go into that discussion, I encourage you to think carefully about what you are prepared to do if he is either unable or unwilling to hear you because you will have to be ready to tell him what the consequences will be if he continues doing what he is doing and you need to be prepared to go through with those consequences.
I don't know how far things have gone and how long this has been going on but as a minimum you should stop going on holidays you can't afford. If he wants to go ahead anyway, let him and see if that might wake him up. I think you also need to split all things 50/50 rather than pay for all bills or take on some other expense in full. This, I hope will make him more aware of the costs of everything. Water, electricity etc are ongoing costs and where insurances are fixed for a year, water and electricity bills aren't and you don't always get to control what they will be. For example, if the weather happens to be particularly cold and you have to turn your heating up, you will be paying more unless you want to sit in the cold and let your kids freeze too. If you are responsible for the kids' hobbies, the piano tutor can also increase prices with inflation whereas insurance costs are quoted for the year in advance and he knows exactly what it is and doesn't have to worry about things like that. He also can't take money from the emergency fund on to spend on something that isn't an emergency. If he wants to continue, you will have to start keeping a separate emergency fund that is just for your emergencies and he will have to keep his own etc. If there are house emergencies or another kind that needs a joint contribution, you will need to discuss that as and when that occurs. You need to separate your finances as much as you can before you get into a deeper and deeper hole.
Has he always been acting like he is now or is this a sudden change?