Hmmm. You say 'supporting and helping' I see children being used as unpaid child care for the babies, at the expense of their own emotional and social development.
I have a friend who is one of 15. She was the first girl and says her memories of childhood are being a little mother to her younger siblings - she doesn't remember any kisses or hugs from her own mum who I assume was just too busy. She is in her 30s and her youngest sister is still only 11.
I just do not accept that anyone has the emotional resources to raise 12 children. Not unless you run a very tight ship and use your older children effectively as your employees.