All fingers are connected to the hand, thus all fingers can use the weight of the hand to play the note. What requires a little more control is when one part of the hand plays soft while the other plays louder. Things get even more complicated if it is the weaker fingers that need to play louder while the stronger stay more quiet. Depending on your own personal issues, these things can be trained away and practiced quite easily.
What I find works very well is to strengthen the 4th and 5th fingers. Lift your hand in the air, taughten your hand on the side of the 4th and 5th fingers and wiggle you other fingers while keeping those two tight.Then bring your hand to the keys, keeping the muscles tight and feeling the difference between the two.This is the method I was taught a pupil of John O'Connor, a professional pianist and Beethoven expert. It really, really does work!