My ex goes to court and tells the judge how broke he is and that he owes his lawyer a ton of money but that he will barter with the lawyer.

My understanding is bartering is considered income for both parties and should be added into the calculation of income. The legal aid attorneys are not available, too busy, and I have to fight this alone in court.

How do I best show this in court?

New york state

First off you have to go by what is and not what's about to be. So if he shows tax returns stating income then you would have to prove it as separate income.

That won't be until after next year or beyond.

The judge asks for current up-to-date records of income in determing support payments. That's how he just got it lowered because of workmans comp. Since he has already admitted in prior court proceedings that he bartered with his lawyer for services, I will present it as income he is hiding. He didn't show it last year (when he did the work) and the lawyer is still providing services this year.