My personal opinion in this is your lack of empathy is ok. The best advice I can give you is that the real world when you move out of your parents house is based on hard work + money + working towards self happiness + learning to be better members of society. That's basically what being an adult is about. Some people like your mom never grow up or have significant personality flaws that make them difficult to be around. I don't think you need to say anything to them. My guess is they are in their 40-60s so they are well beyond grown adults and don't need you to play mediator.

If I were in your position, I would do this. Work super hard in school and set yourself up with a good job after school. Get out on your own and get your life stable (meaning get used to being financially independent on your own). During this time, just keep in touch with your parents on a casual level. Just check in on them, see how they are doing, etc but don't get pulled into the drama. Once you are stable you can try to give them advice based on your life experiences. You will grow like crazy as a person from now until your mid 20s.

Know the issue of money + arguing is not your problem - it is your parents. They appear to be financially irresponsible (your parents aren't the only one) so it's their problem to sort out. Learn from their mistakes. The best decisions you can make in regards to money is never buy anything you don't have money in the bank to pay for at that time and always keep a stash of money liquid that will keep you afloat for 4-6 mo in case you ever lose a job or something. Basically do the opposite of your mom - don't overspend and live frugally. Know all those people that buy nice cars, have nice purses, etc - the vast majority of them are draining bank accounts as fast as they can fill them up.