He can easily hire an accounting firm to refile taxes quickly. Whether he can get an updated NOA back within 50 days is another matter and is in the hands of CRA (and completely out of his control).
Additionally, as someone else here said, even if the NOA is refiled to include the foreign income, it's not guaranteed that IRCC will consider the foreign income in LICO. Here's the specific language off the IRCC web site. Note the word "can" (vs. "will").
As a rule, financial resources must originate from Canadian sources. An officer
can, however, consider income received from foreign sources if it was declared by the sponsor to the Canada Revenue Agency (CRA) and appears on their Notice of Assessment (NOA). It is important to note that income abroad may not be a reliable indicator of future or stable employment in Canada. IRCC staff cannot easily verify if foreign income can be transferred to Canada and converting foreign income into Canadian dollars can be resource-intensive. In cases of default, collection and litigation, it is easier to recover income from Canadian sources.
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/permanent-residence/non-economic-classes/family-class-assessing-sponsor.html