AP level courses are university level courses taken in high school by students. The courses are graded on exams for the most part but AP Studio Art requires a portfolio. They are designed and administered by College Board Inc. They require university level academic skills. The reason to take the courses in high school is to impress university admissions officers by demonstrating that you are university-ready. Most universities that are selective recognise scores of 4 and 5 out of a scale of 1-5 and many will allow a student to opt out of core courses and proceed to electives or get started on coursework related to your major if you have achieved a 4 or 5 in your AP course. Most universities have general education or core course requirements as well as the coursework required for whatever major(s) or minor you do for your degree. It's nice to get gen ed over and done with in a free high school instead of paying $$$ to do it in your first year of university. Some universities wont even look at an application unless the majority of your courses are AP level.
Why do you need to go to college for 4 years and then another college to be a Dr, lawyer etc? And how does anyone afford 8 years college?
Universities aim to produce a very well rounded and versatile graduate. Most universities in the US require a wide variety of courses in different subjects. A grad with a bachelors degree in any subject from a good university will probably have passed exams in calc 3, physics, statistics, literature, foreign language, psychology, a few history courses, etc. as well as whatever courses constituted their major and minor subjects. Even if your degree is in engineering and you go straight into a job in the field you will have done writing, humanities, foreign language and other courses along the way to your degree. Once you have graduated, you are equipped to choose a profession.
DS is entering his senior year and will graduate with a major in biology and minor in chemistry. He could choose to go to law school or med/dentistry/pharmacy/veterinary school but would have to pass the LSAT or MCAT or whatever other standardised testing is required for application to those professional schools. A neighbour of mine did a degree in microbiology and has worked as an analyst in an investment firm since graduation. DD1 has a degree in economics. The path to the BA required six quarters of Humanities, Civilization Studies and the Arts, Natural and Mathematical Sciences, Social Sciences and then all the major coursework in econ. This was gen ed on top of AP coursework that qualified for credit. A childhood friend of DD1's did a major in Mandarin and minor in premed so she had all that coursework plus the gen ed requirements. She is now in med school. When she is finished med school she will specialise and that will take another few years.
You afford college by a combination of financial aid, loans, working your way through, and flying by the seat of your pants. DD1 repaid one of her loans while still in university. She only really took a few days off per year from studying and working for all four years. She probably has enough saved to allow her to go to law school full time if she were to decide to go at this point, having worked for two years. Some people do it this way.
The VA (Veterans Administration) is a whole department of government devoted to care of vets. It does a terrible job, and as suggested by a PP it is one of the reasons some Americans are suspicious of any NHS type of policy departure in the US. exBIL did his med school psych rotation in his local VA hospital about twenty years ago and was shocked to his core at the terrible VA MH services. He saw patients who had been treated for the wrong illness, medicated, and barely functional, since the end of the Vietnam war -- people treated for schizophrenia when the problem was ptsd or bipolar, etc. ExBIL suspected the VA tended to try to hide or mask combat related MH issues. The alternative that he also considered was that VA psychiatrists in the hospital he did his rotation in were incompetent.