Yes, COPD is life threatening.
Quote: I think my doc told my dad it was 30%...
I presume that "30%" means "30% of lung tissue is damaged". People survive with a single lung.
Of course if "30%" "70% of lung tissue is damaged", the situation is much more serious.
Your dad should not smoke--and he should not be around smokers. The air in his living quarters should be as pure as possible--no air fresheners, air sweetners, scented candles.... He should stay inside when the outside air quality is unhealthy.
His lungs have been damaged. Yes, his life will be more limited now, but he has a choice between limitations and death.