How could I make a parachute like effect where the player is constantly falling until he hits (or approaches) ground, but also have the player to be able to control movement left right backwards and forwards?

What you need to do are these steps to your player falling code :-

1).reduce gravity var to slow down falling
2).don't accept jump inputs in your code
3).left,right,forward,back keys can remain the same as movement on ground

That should do it !

i'll try it and let you know if it works, thanks.