As a general rule, international students in Canada are required to pay tax on any income that they earn while in the country. This includes income from employment, business, or other sources. Whether or not your friend is required to file a tax return in Canada will depend on the amount of his income and any deductions or credits that he is eligible for.
In Canada, individuals are generally required to file a tax return if they have income from any source in Canada, even if the income is less than the basic personal amount (which is currently CAD 12,069 for the 2021 tax year). However, if your friend did not earn any income or if his income was below the basic personal amount, he may not be required to file a tax return.
It is important to note that even if your friend is not required to file a tax return, he may still be required to pay tax on any income that he earns. For example, if he received scholarship income or income from employment, the payer of the income may be required to withhold tax from the payment and remit it to the Canada Revenue Agency (CRA). In this case, your friend may be required to file a tax return to report his total income and claim any tax credits or deductions to which he is entitled.
If your friend is unsure about his tax obligations or if he has questions about how to file a tax return in Canada, I recommend that he seek the advice of a qualified
tax professional or consult with the CRA for more information. The CRA has a number of resources available to help international students understand their tax obligations and assist them with filing their tax returns.