Child Support: Defendent Not Seen Or Hear From In Ten Years

My ex was ordered to pay child support in the amount of $500 per month for three children back in 2012 in Massachusetts. He made payments for three months before becoming unemployed for a second time.

The last time we heard from him was in 2014, and his family has not seen or heard from him since 2015 (allegedly). In that time he has not had a driver's license, been employed or paid taxes, or been arrested.

His family never reported him missing because he was an addict and prior to the last time he spoke to them, he was travelling like a nomad and seemed very mentally unstable. They don't know his last location. I think they're afraid to learn what happened to him and would rather believe he's doing fine somewhere. I never reported him missing because he was high-conflict and put my kids through the ringer. The state never did anything because I never collected any benefits, so he didn't owe the state anything. Right now he owes me over $70k.

Now my kids are 20, 18, and 14. Their father being MIA has made it so the older two (and eventually my third) do not qualify for financial aid and needed student loans.

I'm wondering if there is any benefit to hiring a PI to find him, or if there is a way to report him missing after all this time. I know my 14 year old would still qualify for social security benefits, but other than that is there really a point? His family won't speak to me about it at all.