Question: As Rameses is getting dressed by his servants, Nefretiri stops one servant and takes a sword from him. The shot then cuts to Rameses getting dressed and then Nefretiri comes to give him the sword. What exactly did she do with it: did she stab her dead son (who is placed on that statue), or did she do something else?
Answer: I have always thought she stabbed her dead son. It's obvious she does something with it other than just give it to Rameses.
She doesn't do anything other than give him the sword. She's trying to dramatically convince Ramses to kill Moses. In countless stories, one character will tell another character to kill someone while handing them a weapon.
Answer: She didn't do anything with it. She took the sword so she could help dress her husband herself.
Answer: She gave the sword to Ramses and told him to bring it back with Moses' blood on it.