Medicaid at age 19?

My wife and I are married have have one child. I make $90k a year. Our son turns 19 in January. In 2023 he will be living at home with us, doing some volunteer work and working a part time job. We estimated he’ll earn about $8500 in 2023. He has never been on my insurance from work as it was ludicrously expensive. He and his Mom were on a pre-ACA HDHP with an HSA. We have dropped that coverage recently. I do not plan to claim him as a dependent in 2023.

We told him to just see what health insurance would cost, so he went to healthcare.gov and put in all his info. They said he made too little and that his information would be sent to Florida Medicaid. Three weeks later, we start getting tons of mail saying he’s approved for medicaid. He’s received his medicaid card, health and dental insurance cards from Aetna. They’ve even assigned him a PCP. No mention of any premiums or cost.

We don’t want to look a gift horse in the mouth, but something seems too good to be true here. Is it possible for an adult living at home with his parents, making $8,500 a year, can qualify for medicaid and get free health and dental insurance?