I am ignorant of what Catholic chaplains do in the military now. Do they only minister to Catholics (ie. hold mass, listen to confessions)? Also, do they now celebrate the Sacrament of Matrimony in the military for Catholics?
Yes to all of your questions. They also administer support to non-Catholics who need guidance on whatever problems they have. They obviously can’t provide any confession or give communion to non-Catholics, but they can provide any kinds of psychological needs.