@nivinator By this point on the story (chp 4) his relationship is marked by being emotionally distant with Icchi, neglectful, and yet controlling, and restrictive.
Later on the manga will reveal why their relationship is so complicated, why he has put so much effort on being distant and stern, and why he acts this way towards Icchi.
Part of the key establishment of the character is to show that they are not a normal family.