Overheating and now, engine knocks bad

My sister's 2000 Alero 2.4L overheated the other day. She topped the resovior with water. Engine knocks really bad now...I think the connecting rod bearings were on their way out already due to low oil the few times she neglected to top it up. Engine knocks so bad I told her not to even start it up anymore.
I checked it today, water pump is leaking and just spews the coolant out like crazy.
Has any one here every replaced the connecting rod bearings?
Could overheating really cause the engine to knock so bad? What other advise or hints can anyone provide?

Please help ASAP as I plan to start fixing this soon.

Doesnt sound good.

Overheating whether it was ran low on oil or coolant can ruin all the bearing.

I would make sure thier isnt an air pocket trapped in the cooling system as this will allow it to overheat again, soon!
And I would change the oil and filter asap to see if that'll clear up any knock.

But most likly,
thier is more wrong then just a rod bearing.

Could have easily warped the head too.
All of which can add to major ca$h if internal repairs are needed.

Hope that helps and Good Luck!