You're right, the mortgage interest is deductible. Also, I believe some of the medical bills will be deductible as well (medical expenses beyond a certain percentage of your income are deductible).
So no, she won't pay 28k federal tax.
That being said - is your $3,000 in child support and alimony in lieu of having to pay anything for D16's treatment? Because eating disorder treatment can be hideously expensive, bankrupting families.
