You're right; "life" seldom means life. Yates' sentence to life in Texas means parole consideration at 40 years. Ironically, this approach makes sense. Death panalty advocates in Texas actually support the "life with parole at 40" because it ties the hands of future liberal governors who might be tempted to commute a death penalty sentence to "life" (and have to face the political fallout of doing so).
"Death" means death; no ambiguity.