You could correct the subject line..

Stone giant's CR is 8 (or 9 if it is an elder). An elder could be a sorcerer (3-6 level) as well (10% chance) in which case the CR is higher. So most likely you can take on it and win.
Be mindful of the terrain. If possible the druid could cast
entangle to make things difficult for the giant. As mentioned above
grease is also superb.
Although I would suggest that if the DM really wants you to talk to the giant then you'd better do it. Maybe he has some story related hooks in his mind. So kill it after you have talked to it
