My boss pays 50% of my health insurance and 100% of my coworker's. Is there a labor law against this?

I just feel it is very unfair. 1st of all, the man he pays 100% for is new and 2nd, he gets paid 3x as much as I do. My boss also pays for 50% of everyone else's insurance in the company. They supposedly had an agreement prior to hiring the new guy. I just feel its not right
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They can do whatever they want so long as it is not discriminatory. Or as long as it doesn't violate union contracts. The other guy may have more experience, different work requirements, was a better negotiator. You don't know what the reason is. Just because he is newer than you doesn't mean he should be paid the same as you.
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