You're being lied to. There's no way to even say that because the estimates on how many undocumented there are in this country are wildly inaccurate. Like millions of people off.
For reference, all three states that decided to give Medicaid to illegal immigrants (California, Minnesota and Illinois) severely underestimated ho many people there were and now suffering from severe budget shortfalls. So they all had to scale back.
For those states that don't offer Medicaid to illegal immigrants, the hospitals still have to bear the brunt of the cost whenever they give birth, have an accident, etc.
Democratic States Expanded Healthcare to Undocumented Immigrants. Now They’re Rolling It Back.