Your son needs to see a therapist, and you need to to back off. He is an adult and, if he cannot start graduate school on his own, he should take a break and get his life together.
Yes, he is your son, and you are his parent. However, he is not a child or even a teen. he is in his early 20s, and he should be able to make decisions about his future without you putting pressure on him to do the things that you believe he should do.
Almost every single one of your posts over the last four years about your son has indicated that you are still treating him as a child, trying to solve his problems and trying to determine how he lives his life. Almost everything that you have posted about your son’s responses have indicted that he is responding with a mixture of resentment and dependence.
You may also benefit from seeing a therapist about your relationship with your son, and maybe you should see one together.