Convincing embassy staff he's coming to study at age of 64 is going to be a difficult task with almost certain outcome - denial.
He cannot do what he wants, live in the US indefinitely without a valid path.
There's only four ways of coming to the US on permanent basis:
- Employment
- Asylum
- Visa diversity program (Green Card Lottery)
- Sponsorship by spouse, parent, child or sibling (siblings are out of the question due to super long wait)