if he has no income and your state is expanding its program your son will qualify for medicaid. you should begin searching his options at healthcare. gov. if your state is not expanding medicaid and he doesn't qualify he may get significant financial help to pay for a private insurance policy. if he remains unemployed and for whatever reason cannot find affordable insurance he will not be penalized for failing to have insurance.
my son is a recent graduate of law school but he has been unable to find employment yet. . he has absolutely no income and no assets and no health care needs to speak of. so he does not need health insurance (although it would be nice to have) and he has no income with which to pay premiums so what are his choices? medicaid? under other circumstances no longer being a minor he would not qualify for medicaid.