2009 Dodge charger Needs new engine??????

I have a 2009 dodge charger that while I was driving slowly lost RPMS and
came to a smooth stop. When I pulled to the shoulder and tried to crank it
back up it did nothing but make a sputtering sound as if the battery were
dead or starter was bad. There was never any smoke, smell or check engine
or oil lights that appeared. I have had two different mechanics look at it and
tell me that I need a new motor because the timing chain broke. However as
of right now the car still cranks, runs and drives but loses oil pressure. I am
confused about this and just want to know if the car would in fact need a new
engine if the timing belt broke. Also am confused by the fact that it runs and
drives with this issue. I would've thought that it would not. Thank you for any
answers you can provide