Helseth was much more insidious than any Imperial in my opinion. It's like he was so determined to deny his Dunmer blood that he didn't just practice ruthless political tactics but went out of his way to destroy traditional Dunmer society.
I can only imagine the smile on his face when he heard of the deaths of Ayem and Seht, and he probably ripped those clipped ears of his after he heard Vehk was gone too. At least he didn't have free reign over the country for long.
But Helseth is Barenziah's son.
And at the time of Tribunal, Barenziah is still very much alive.
I dont really think Helseth has that much to say, I think it is all bluff and bluster.
I dont think his mother, after all that time and all she witnessed and went through, would release any hold she might have.
Barenziah is a master politician.
Helseth, like the son of Potema, I think they only exist as extensions of their mothers really.
Maybe she died at Red Year, but I think quite likely not. As Terry Pratchett′s Cohen the Barbarian, surviving is a habit you get good at with age.
Similarly I also think Fyr is still alive.