Help me find novel title / author

With all the help of our full-blown technology era, I hope to find the Title and author of a book I read years ago. I found the book in the Bloemfontein library. I read it in 1988-1989. The plot goes like this:

It's all about a family: overbearing mother, weaker father and some kids (3-5)
The father runs his own grocery store and the family is barely making ends meet
The eldest son is very responsible and gifted in different things.
He don't have the opportunity to go study and must always help in the store
He is very good at business and eventually builts the business up to a excellent store (maybe chains of stores) and lots of money is made through his input.
However, he is always rejected ,his giftedness downplayed in comparison to his siblings who are allowed to live out their fantasies which never amounts to anything.The sister for instance think she's artistic and lots of money is spent on her 'hat-design' idea which is a flop. The eldest son drew a beautiful picture of a bird as a child.His mother hid it away, not encouraging him at all.

In the end the eldest son developed resentment towards his family since he always had to just work and supply for their every whim without any recognition or chance to live out his own dreams. The father was a weak character whereas the mother was strong and scheming. She deliberately held back the eldest in order to use his talents to enable the rest to live comfortably, knowing none of the rest would have been able to achieve what he did.
The end is sad, depressing, with resentment and bitterness

Anybody read this novel ? Please let me know.