Thirty-three years ago, David Adelman used his bar mitzvah money to buy a $2,000 stake in Campus Apartments, the student housing business owned by his mother’s lifelong friend Alan Horwitz. It paved Adelman’s entry into what’s now a national network of student apartments that he has come to lead.

Now “Uncle Alan,” as he was once affectionately known, has returned the favor 1,000-fold with a $2 million donation to another venture currently helmed by Adelman: the plaza commemorating Holocaust victims that opens Monday on the Benjamin Franklin Parkway in Center City.