Player wants to hold a crossbow (crossbow expert) and a Longsword at the same time, take the attack action at lvl 5, to deliver an unarmed strike with the first attack (a kick) proccing Agile Parry, then drop the sword, shoot the crossbow with the second attack during the attack action and use the crossbow expert's bonus action to fire the crossbow again (with hand free) and then pick up the sword.
Sorry, I might be missing something, but why does he need to drop the sword at all? Assuming both the crossbow and the longsword are kensei weapons, couldn't he simply attack with an unarmed strike (proccing agile parry ), attack with either the longsword or the crossbow ( both are one handed weapons ) and proc the bonus attack with the crossbow due to Crossbow Expert?
Or just avoid the longsword altogether, since agile parry doesn't require a melee weapon, but just a kensei weapon?