If I play a Reversal off of Healer with Nakoruru, does the effect of Father Bull resolve? Or must be absolutely be blocked as stated on Father Bull?

In short, no.

"If you play an attack as a reversal after BLOCKING this attack"

Which you are not doing, you are playing an attack as a reversal as IF you had blocked

if you block this attack and play a reversal AS IF you blocked the attack are the same thing, the ability says ASIF you blocked the attack, so its as if he did block it with a card

Stamp for Smazzy for getting the card text right.

Buzzer for Awaken. Sorry dude.

a simpe stamp for the right answer would have been enough

Awaken said:

Acknowledged. In past when there has been conflicting answers in the rulings, and I have not addressed specifically which one is right, and which one is not, it has lead to confusion, and people requesting further clarification.

I was trying to be as concise as possible in as little text as possible. My apologies if I offended.

no problem, thanks for the apology i understand your reason behind your response now.....carry on