I had a giant clot when I stood up and for the first time and showered the next morning. After that it settled down and was like a really heavy period.
I laboured until 9cm and then had a c-section.

As far as I remember it was lighter than the lochia from my vaginal birth.

Your Mum must have had some bleeding because the blood vessels where the placenta is joined to the uterus wall 'bleed' as they seal off. The places where it joined falls off like scabs otherwise it would scar and implantation for the next baby couldn't occur. I would say that it's impossible to birth and not bleed.