Will the NY courts consider an inheritance of $100,00s as a "substantial change in circumstance" to warrant a modification of child support?

The inheritance by itself will not necessarily trigger any court case in regards to child support.  However, you should keep in mind that the mother has the statutory right to seek modification of a child support order if:  1) Either parties' adjusted gross income changes by at least 15% since the last order; or, 2) Three years have passed since the date of the last order.   The Courts and the Child Support Enforcement Unit do not keep track of an individuals income or inheritance.  So it will be up to the mother to file, and if it has been three years or more, she will not even need to have knowledge about the inheritance to ask for an increase in support.   The inheritance is called a "discretionary income" to be added to his adjusted gross income.  Therefore, the Court can, but is not mandated, to include the inheritance when determining a child support order.  Given that inheritance income is usually a one time payment, and not paid on a consistent basis, he has a strong argument to make why it should not be included in his adjusted gross income for any modification of a child support order