The writer of "Father, Dear Father" sees a vast difference between his mother and his grandmother - and this difference is the critical comparison being alluded to throughout the piece.
We learn that his mother is "highly qualified", suggesting she is well-educated, works in some sort of professional field and earns good money - and yet he describes her as "highly strung, tense and nervous".
He then compares that state of mind to his semi-literate grandmother who is content and happy with her life: "at peace with her pots, pans, her flowers and garden, her Bhagvad Gita and scriptures.".
The final line makes it pretty clear what the author is pondering, and what difference he sees between these two female role models in his life, and the paths they have taken:
"Do you think literacy makes us, restless, afraid and frustrated?"
The author is trying to establish whether school work and studying actually has a negative impact on someone's well-being, or whether he should really be focusing on studies as much as his father would expect him to.