Telling a mourner, "Please sit"

Hi,

In general, one who comes to visit someone may tell the visitee to sit, if the visitee rises to honor him. However, one may not tell a mourner to sit down, for that would send a subtle message, "Sit/remain in your mourning."

(Code of Jewish Law Yoreh Deah 376:2)

Have a good day,
Mordechai