Is he registered with the Office of Disabilities? Does he have a therapist or psychiatrist who can communicate with professors and deans?
Once admitted to an Ivy, they tend to be very supportive and help with challenges. I would seek accommodations that can help him with the stress if he has not done so.
There may also be groups for new students experiencing loneliness. COVID has sent a lot of students into a state of depression and anxiety so there may be resources for that too.
I don’t know which ivy and whether there is a house system but housing systems may afford ways to meet people and have staff that help too.
For accommodations, you can write a letter for a professional to sign, after researching accommodations for OCD and anxiety. Just list them in the letter. We found professionals appreciated just signing and not doing the actual letter writing and research!
The Office of Disabilities gives the student a letter for each professor and then the student negotiates with the professor. But was also found that a doctor or other professional can communicate with a dean and the dean will tell the professor to accommodate.
Things like extensions on papers/projects, extra time on exams and tests, and even reduced course load can really reduce stress.