The BBC, as always, with its full SJW hat on, gets it badly wrong:
Satbir Singh is a British citizen who is unable to bring his wife to the UK from India, because his more than £60,000 a year income comes from more than one source.
I went through this with daughter. She had income from three sources - her part time job, research assistant work at her University, and research assistant work with our company. The big question was whether she would build up enough income from her three jobs, or eventually reach the full income requirement from her university job.
Here are the rules. And remember this guy is on £60k per year, according to the BBC - more than three times the current £18,600 requirement.
Category A - if any of his sources of income is a job that pays £18,600 or more a year, salaried or not, he can apply to bring his wife over after 6 months in the role (lowest salary in the period counts, non-salaried get it slightly easier and it is total gross income over that 6 months.) And you can add non-employment income, a savings contribution or pensions.
Category B - (and the example c in the rules is a good one) - this is how my lass qualified in the end.
Part 1: Gross up your employment over the last 6 months and do you exceed £18,600 annual equivalent? If you are salaried, you can use your current salary rate. If you are non-salaried or have multiple earnings, do some trivial arithmetic.
Part 2: Did you earn more that £18,600 over the last 12 months?
Pass both parts and you can apply. And you can count your partner's income (if they are in the UK with permission to work) and, as above, non-employment income and pensions count for both parts and a savings contribution can be used for Part 1 but not Part 2.)
So, I reckon somebody on £60,000 p.a., an average £5k per month, would be trivially able to meet category B after about 3 months and 22 days, before adjusting for lumpiness of income? That would be enough time to earn £18,666.67 - covering you for both Parts 1 and 2 of Category B.
There are various adjustments, to the benefit of the applicant, for sick leave (and maternity, paternity, adoption and parental leave) and other categories, C through G, for different circumstances.
I call "Bollocks" on the particular instance (rather than that there are specific people who have particular issues with the system.) Unless, of course, his income is undeclared - but that's his problem, not HMG's.