The thing about public schools as compared to private is that with private, you pay for most everything up front, whether or not you use it. Massages, ADHD coaches, tutors, single dorm rooms, ski cabins…
In public school, there are separate fees for everything, although there are online and flesh and blood coaches available. Before they enter their major, students may find classes to be larger than high school, and some discussion sections led by TAs instead of profs. But even at the UW, upper division courses may be much smaller, depending on department. It can take students a while to find their footing, but resources are available, even if they don’t qualify for disability support.
If they do qualify for disability support, they may need to restablish it at the beginning of each new school year.
This may take prodding, but having a formal record is helpful as is priority registration so you can get profs you know you can work with.
There is no shame in deciding you need to transfer, or in having a term or even a whole year that seems like a setback. I know lots of people my own age, who went on to very successful careers after changing schools, or taking way more than four yrs to earn their undergrad degree.
It will be good experience for when they go for their ph.d, and their supervising prof keeps changing the parameters!