Yes and no. It is a “sacrament of the living” in that it is for those in the state of grace, not in mortal sin. It’s a supernatural food that strengthens us, but food does nothing for the dead–in fact, it is a sacrilege to receive it in the state of mortal sin:
1 Cor. 11:27 Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord.