[Edward Tinker]

We are not doubting you, and some troops met up with Russians but perhaps it was the occupation right after the war?

On 12 April 1945, the day of President Roosevelt's death and eighteen days before the Russians took Berlin, Ninth U.S. Army units crossed the Elbe River near Magdeburg, some fifty miles from the German capital. (See Map X inside back cover.) They established a second bridgehead farther south on the following day. German counterattacks forced them to withdraw from the northern position on the 14th, but the Americans held the southern bridgehead. These elements were ordered to hold in place while other units arriving at the Elbe were turned toward objectives south and north along the west bank of the river. On 5 May, a week before the Russians liberated Prague, the Third U.S. Army pushed spearheads inside the Czechoslovak frontier and, on the day the war ended, was in a position to advance in force to the Czechoslovak capital. Despite the pleas of the Czechoslovak leaders and the appeals of Mr. Churchill, these units were not sent forward. Many observers have concluded that only a political decision, perhaps made weeks before, could have held General Dwight D. Eisenhower's forces at the Elbe. Careful examination of the Supreme Commander's action indicates that he halted his troops short of Berlin and Prague for military reasons only.

here is one website info

Following Germany's World War II surrender, Berlin was occupied by Armed Forces of Britain, France, the Soviet Union, and the United States. US forces took charge of America's Occupation Sector in July 1945.
First US troops in Berlin were from the 2nd "Hell on Wheels" Armored Division who were soon replaced by elements of the 82nd "All American" Airborne Division and 78th "Lightening" Infantry Division. Shortly, these two divisions were withdrawn; replaced by the 3rd "Old Guard" Infantry Regiment which was inactivated in 1946.
3rd Battalion, 16th Infantry "Rangers" of the 1st Infantry Division, and 16th Constabulary Squadron (Separate) occupied Berlin's US Sector from 1946 until 1950 when 6th Infantry Regiment "GATORS" was activated to replace them.

If your dad and friend were stationed there, it could have been right after the war, during occupation duty and trust me, i have seen real stories of a box of lugers (30-40 of them) that were hidden in an attic and found years later - Berlin was pretty leveled, but much still standing.