I am almost convinced that either Butters' sword will kill the Hunger Demon or that Harry will find a way to release only Thomas' human part from Demonreach, separating him from the Hunger Demon. This would mean, the Hunger would stay in stasis.
Either way, I think Jim will write it so that Thomas becomes human. I think, in Jim's opinion Thomas' character has become boring and it needs some "juice", not in form of a power upgrade, but as some sort of downgrade and to show his struggles in finding a new purpose and identity. Especially now that Thomas has seemingly come to accept his vampire nature and found a way to live with it.
Thomas in story has mostly been additional muscle with banter and family bonus and vampire troubles.
But there is so much more to him. All the internal struggles, the difficult family situation (Papa Raith, White Court, wizard descendant) makes him interesting, but this has mostly been in the background and only brought into light when it was important for the story. I think it's a pity: there is so much more to Thomas than just the pretty muscle with some deniable problems. Deniable is not my opinion, it's just how it feels to me that Harry sometimes behaves toward his brother. I was a bit shocked at his dismissive reaction to Thomas revealing that Justine was pregnant.
So I think, he will become fully human, maybe during his time of adjustment, he finds out that he has a little magical talent, maybe not. Maybe it's just weak like some paranetters.
And there is of course still the Justine situation: there will be grief, a search going on for the woman and the baby and who knows how this will turn out.
And then, but not too soon, he will find out that he was meant for Amoraccius from the beginning.
Thomas taking up the sword after becoming human is in my opinion the only solution for him to stay in Harry's world, to become "useful" again. From the story's perspective.
The other would be becoming a wizard, but I don't think his talent would be relevant in future events, meaning the BAT, Outsiders breaking through the Gates and so on. But the Sword of Love will be.