I was born in a time when kids were supposed to sleep with their backs up and mothers were supposed to wash their nipples using antibacterial before breastfeeding...!

Sometime before that there was a time (at least around here) were kids were supposed to eat sour cream porridge from early life.

Of course kids died left and right, but the logic was, if so many died following the best practices, how many wouldn't have died if babies were left drinking only milk! (Retold as best I can describe it from what an older person in the family told me.)

All this is before we start talking about parenting fads like "no rules parenting" (not sure about the exact English term) which must have caused untold harm.

So creds to your dad for finding the correct advice and sticking with it.