Game really doesn't like rescuing his Dad after breaking his pact. I had similar.
My game was
Refuse to renew the pact
Then we went more or less straight to rescue the Duke
Then we had a couple of conversations in camp with Wyll and his Dad and went to find Ansur
Once we'd killed Ansur Wyll decided, pretty much out of nowhere, that he was the Blade of Avernus for some unknown reason.
Given he was no longer pacted it made little sense. He was standing by Ansur's corpse at the time, only him, Lae'zel and Astarion present.
He managed to stay that for about 30 seconds, which was as long as it took me to get to camp, then his Dad asked him to be Duke and he accepted that.
But the conversations made it very muddled and unclear which way he was going to go although Mizora pouted a bit that I'd made her look an idiot
Throughout it all Wyll's main conversation was wanting to make a beef stew and serve it with a pint of beer - which seemed weird to say the least - he seemed to mention it every time I spoke to him throughout the quest.
