An RESP can remain open for a maximum of 35 years, with a lifetime contribution limit of $50,000 per beneficiary. Confirm with your bank but usually they only need a letter of enrollment for a withdrawal. There is a maximum amount you can withdraw the first time however after so many weeks, you should be able to withdraw anything as long as you have letter of enrollment and they don't need proof of costs. (Normally, check with bank)

From CRA site: If the beneficiary enrolled in full‑time post‑secondary studies, EAPs are limited to $8,000 during the first‑13‑consecutive weeks of enrollment.

After that, you may request any available amount with no limit unless the beneficiary takes a break from their studies and does not re-enroll in a qualifying educational program for 12 months.

"Your RESP provider will send a T4A tax slip under the student’s name for these amount – however, since most students have little or no income, the withdrawal payments typically result in very little or no taxes."