One thing I would point out is that since IIRC sometime during the Clinton era, Congress mandated that these children of illegals be admitted to public schools, an unfunded mandate, as it were. On average, that probably is $10K/student per year.
So, assuming a{n illegal}student meets the minimum requirement for in-state tuition, 3 years in TX schools, the state or local community has already had to pay (or invested) three years fully of his/her education. With no co-pay whatsoever.
Not exactly. It was Plyler v. Doe, a 1982 SCOTUS case. Brennan, Marshall, Blackmun, Powell, Stevens, 5 to 4.