In memory of Rabbi Gavriel & Rebbetzin Rivkah Holtzberg HYD - Shluchim to Mumbai, India*
You write that your parents work Monday thru Friday from 9-6 PM. This means they work on Shabbos! If this is the case, see to it that from here on they don’t work on Shabbos. This is in their best interest physically and spiritually.
p. 253 Igros Kodesh Volume 29
*As a practical matter, since each person’s circumstances are always different, one must use the guidance above as general instruction. The exact application at any given time must be discussed with a competent rabbi, or/and a counselor of Torah, a Mashpia.