Can this rear wheel be straightened or does it need to be replaced?
That rim is dead.  You need to replace the rim at least.

Being Aluminium it won't straighten, it will crack if you un-bend it.

If you choose to continue riding it then you may get more punctures, and you will be damaging the rear brake pad with every revolution./

If the tube/tyre is still holding air then they're probably ok to reuse.