Hi Iria,
It does help.
I've just been double checking what I had for his children and I don't believe there were any girl children so it should make it easy to find two of the sons on the return for 1901:
Ludwig Oppenheimer (jnr) b: 1870 in Chorlton m: 1897 to Jessie Northrop in Chorlton
Albert Oppenheimer b: 1873 in Chorlton m: 1899 to either Grace Newton or Mary Wright in Stockport
Charles Oppenheimer b: 1875 Chorlton m: 1903 to either Clara Cartali or Constance Taylor in Chorlton
William Renwick Oppenheimer b: 1877 m: 1904 to either Caroline Goodwin or Edith Lee in Bucklow
Obviously Charles and William won't be on the 1901 census, but it doesn't hurt to let you know.

Many thanks
Kirsten