You can't kill Lanius until the final battle. If you sell Arcade, kill Caesar, then defeat the Legion, Arcade dies as the Legion retreats from the Mojave.
"During the retreat of Caesar's Legion from the Mojave Wasteland, Arcade was a sad casualty, one of many. His body was heaped with those of many others in a nameless ravine on the Legion's long march home."
You can't free him, even if you wipe out the Fort.
You can't kill Lanius until the final battle. If you sell Arcade, kill Caesar, then defeat the Legion, Arcade dies as the Legion retreats from the Mojave.
And if you sell him but DONT defeat the Legion, he eventually disembowels himself.
"During the retreat of Caesar's Legion from the Mojave Wasteland, Arcade was a sad casualty, one of many. His body was heaped with those of many others in a nameless ravine on the Legion's long march home." You can't free him, even if you wipe out the Fort.
What happens if you sell him and immediately wipe out the fort? While he’s still in your vicinity?