My dad had 2.5 million dollars five years ago and he has barely touched it how much should he have in the bank now after collecting interest for five years?

The amount your dad has now depends on the interest rate and whether it was compounded. For example, if he had a 2% annual interest rate compounded annually, he would have approximately $2.76 million after five years. However, without knowing the specific interest rate, it's impossible to give an exact figure. You can use the formula for compound interest to calculate it based on the rate.