my father is religious, I’m not and I don’t care what happens to my body after I die. Burn me, use me to feed stray cats.
To me, wasting money to buy a plot of land so I may be buried with them when I die is a stupid idea.
It is, however, his money. Who am I to disagree with him?
Under most circumstances you will have more time to decide this than your father.
Let him do what he needs. Don’t argue. Again, your decision will likely get to come after he has passed.