Q. Does the prohibition of walking behind a woman apply to following one’s mother?
A. Nitei Gavriel (Yichud 56: 13: p. 367) maintains that when in the street, the prohibition applies. However, in ones home when needed for the honor of the mother it is permitted.
Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as revised by Horav Shlomo and Horav Aharon Miller Shlit’a