A list of free educational programs and courses for Ukrainians.
GBH article about universities that are supporting Ukrainian students.
Edx.org is offering free online courses to Ukrainian students for the foreseeable future (see blog below). I believe the student needs to log in and apply for financial aid to take advantage of the free courses through their university account.
Udemy.com Offers some free courses to everyone including Ukrainians, but it didn’t appear that they waive fees for Ukrainian students specifically.