From the FAQ section of the last rules review they did:
Q: Can weapons be swapped during a combat?
A: No, with the exceptions of pistols and lances which may be exchanged for a different weapon after their first turn special attack.
So, he could drop the pistols and go with his sword and his free dagger, but would not be able to grab his shield.
There are various house rules on this one. Here are a couple the author (at some point, in an interview, which I no longer have!) said seemed reasonable: (1) count pistols as clubs once they have been fired, and (2) allow warriors to change weapons, but not change back since they were dropping the original weapons and would not be able to pick them up again until after the combat. We use both.