Completing IMM 5406

[ZeKanucke]

Here is the situation, for THIS case: My father (the PA) and my mother (Spouse of the PA).
I know that EACH must complete his/her own IMM 5406.
The IRCC asked me to add some extra information, and they ASKED specifically NOT to update via the online application, but the PAPER version - which must be signed by hand.

BUT.
For my father:
On his PAPER FORM
APPLICANT: My father
SPOUSE ... : My mother
FATHER: His father's name
MOTHER: His mother's name

My mother (who was added as a "Family member" on the web site application).
Here is the question - how do I complete my mother's PAPER FORM:
Should I write:
APPLICANT: My mother???
SPOUSE ...: My father (????? - HE is the applicant, my mother)
FATHER: HER father's name
MOTHER: HER mother's name

Or
APPLICANT: My father (even if it's my mother's form)?
SPOUSE ... : My mother (not being the PA, but a family member)
FATHER: HER father's name
MOTHER: HER mother's name

Anybody?