Unless things have changed for 2021, the requirement for "full time" attendance is still there (am referring to "Preparing Your Income Tax Returns" for 2020, Sec 1335).  So it all comes down to how "full time' attendance is defined. I give the following definition from the Alberta Student Aid page:

"Full-time course load

Student Aid considers you a full-time student if you:

• are enrolled in at least 60% of what your school considers a full-time course load, or
• have a permanent disability and are enrolled in at least 40% of a full-time course load
• are attending a licensed private career college in a program that is 12 weeks or longer and has 20+ instruction/practicum hours per week

For example, in a standard undergraduate program, one to two courses per semester is usually considered part-time. Three to five courses is usually considered full-time."

I'm seeing similar answers elsewhere.

In this case, there may be a discrepancy between the CRA definition of "full time" and the educational institution's definition of same.  I would check with the client to find just how many courses were being taken simultaneously.

Hope this helps.

Jo Ruelle