$4.7 million severance case involving a former Facebook Canada executive — how does this even happen?

I came across the recent Facebook Canada case where a former executive reportedly won an appeal involving more than US$4.7 million in compensation/notice-related claims.

It made me curious about how courts calculate notice for senior executives. Is salary the biggest factor, or can things like age, position, length of employment and difficulty finding a similar job dramatically change the amount?