Hair loss can't necessarily be from the mother's father

[so elektrikkxx]

I know it's said that hair loss for guys depends on your maternal grandfather but this can't be true, because many times you see two guys who are brothers and one has more hair than the other, one may be bald and the other has a full head of hair, etc. If hair loss is generally inherited from the same family member, all male siblings would have the same amount of hair and this is usually not the case.

Does anyone have anything to share about this?
I'm just worried because my maternal grandfather has NO hair. I know me losing my hair if at all is years away but still My grandfather on my dad's side had a full head of hair until he died, my mother's maternal grandfather did too, and my dad has a receding hairline but isn't losing much hair at all.