If they confessed it to their priest and repented of it, he probably lifted it.
If not, and the priest knows about it and still gives here communion, he's in dereliction of duty. The Church, unfortunately, has grown lax about these sorts of things since the 1960's.
FYI, no priest could have lifted Hitler's excommunication. Under the Code of Canon Law in force at the time, only the pope can lift the automatic excommunication that comes with assaulting a priest, monk or nun.
FYI--quite obviously, this is balderdash ex-communication of no value or merit. When the Pope does a real excommunication catholics are required to shun you. Had the Pope actually, publicly excommunicated Hitler, and any priest that co-operated with the SS, it almost certainly would have halted the holocaust in its tracks. Did this occur because of your namby-pamby so-called ex-commication? I think not.
Hmm.. And lets think about this a bit. Is George Bush ex-communicated if a federal officer roughs up a suspect that happens to be priest, monk, or nun? Did Hitler personally rough up a priest, monk, or nun? Did Hitler's minions illegally rough up a priest, monk, or nun? If it was illegal, did Hitler explicitly and knowledgeable order it? If he did, who would know? If an ex-communication falls in the forest, with no one to hear it, does it make a sound?