I quite agree with BRL.
The school I learnt with offered discounts for largish up front payments but seemed unable to administer either the account or the discounts satisfactorily (and for my part I couldn't work out the position either).
On a less technical note you may not be happy with your initial choice of flying school or instructor and so payment up front may bind you into a situation that you would rather change.
One further point is that using a credit card to pay for lessons is the best method - there are certain safeguards and insurances that automatically come with these payment methods & if it's your dad's then the school should be able to take the card details without him actually being present (and he gets a bit longer to pay).
Happy learning.