This grill is very much repairable..
First, it needs to be heated and dried out.
Then the cracks/tears need to be filled from the bottom up using a syringe
AMAZON: Syringe 8pcs 12cc Disposable Curved Syringe Irrigation Syringe with Curved Tip
I would fill the cracks in the lip with
AMAZON: J-B Weld 8281 Professional Size Steel Reinforced Epoxy Twin Pack - 10 oz.
J-B Weld has a tensile strength of 3960 PSI and can withstand temperatures up to 550ยบF.
The firebox is fine.. leave it alone, use it as is. The crack is fine. DO NOT try to remove it.