A big congratulations to your brother! I can imagine the joy in the family.
As you earlier mentioned, pressure is good at certain times in a child's life. But most times some kids tend to give up because the pressure becomes unbearable.

Your dad behaves just like mine, he is very reserved too, he hardly smiles and even if you do a great achievement, he just smiles and that's all.

The journey was surely very tough for Hamza, i can imagine how hard he worked to grab his PhD. Congrats to him once again. I'm expecting to read a post of you also becoming a dentist😊