Most if not all states do not calculate the new spouse's income in these situations. It's completely unfair but that's the world of family law.
Likely this is accurate in many or most states. Get confidential legal advice from a local experienced family law attorney.
However, if her new husband has a good income, she is likely to reduce her work hours or even quit. In that case, research too whether the calculations can IMPUTE her income for what she could earn full time* since she could otherwise work. I suggest you don't mention an imputing possibility to her or else she may try to find so other way to stop paying for her portion of expenses. For example, she may decide to find a way to make herself unemployable or 'unable' to work. Sharing information needlessly carries a real risk of sabotaging yourself.
* I believe recent law changes to employment and insurance have redefined full time work to extend as low as 30 hours per week. Find out whether she can work reduced hours and still claim those as her lower earnings.
Common child support questionsChild support guidelines by state