Capiltalisation

Hi

I am currently filling in job application form where one has to give various
examples/tales from life.

I am relating a tale which involves my grandparents, now the query I have
is, I am writing a sentences speaking of my grandparents... (example)

"My grandparents had been married for nearly Forty years and had rarely been
apart. My grandfather bought a cat, while my grandmother bought a dog. My
grandfathers cat ate my grandmothers dog"


Now my question is, should the G in grandmother and the G in grandfather be
capitals?


TIA

Tom Burton


.