Easy way around it. If you're cutting a separate check, then stop. Bump their pay that amount. Yes, it will be taxable, but it will certainly help with the additional costs.
I am not sure it helps... if their pay goes up, their responsibility to pay for healthcare on the exchanges will also go up. Might bump them into a much more expensive bracket on the exchange. Not the same as giving them assistance.
I wonder if the IRS has already made this against the rules. From the article, the tax status of the assistance is immaterial. Substituting a raise for X dollars for the assistance of X dollars probably raises a flag in their system.
after all, NOT violating the $10K bank transaction limit (no matter why) is enough to get you investigated and have your money seized these days.