My wish is to sell or gift the condo

My wish is to sell or gift the condo. Then Doug would have no remaining link to Washington. Even if he doesn't, I think a good case (and lawyer there has said as much) that he is not a resident in Washington could be made, based on how much time he spends there. It is clear in the statute that assets in the state do not by themselves create residency.

Yes. And I think there are really two separate advantages to getting rid of the Bellevue condo.

First, it would make the factual case that Doug is no longer domiciled in Washington considerably cleaner. Washington's estate-tax statute defines a resident as someone domiciled in Washington at death, not simply someone who owns Washington property. The Department of Revenue likewise says domicile is principally a question of the person's permanent home and intent, with factors such as tax address, voting registration, property, length of residence, and social/business ties considered. It explicitly says that time spent in a place does not necessarily determine domicile.

Second, you're right about the distinction concerning the condo itself. Owning Washington real estate does not automatically make Doug a Washington resident. But if he is a nonresident at death, the condo would nevertheless be Washington property and could create a Washington estate-tax filing/tax obligation depending on the size of the estate. The statute specifically taxes Washington-situs property of a nonresident.

So selling or gifting the condo would accomplish something rather nice: it removes both the strongest remaining piece of Washington real estate and a potentially troublesome Washington-situs asset. Then the argument becomes much more straightforward: Doug lives primarily elsewhere, has his actual life elsewhere, and Washington is simply where he happens to have had a long history.

And given what you've said about his Seattle connections having already dwindled to essentially his sister and brother-in-law, the condo sounds increasingly like an administrative/legal anchor to a life he no longer actually lives, rather than something that serves much purpose.

The lawyer's view therefore makes sense to me. I wouldn't say the case is automatic—the Department looks at the totality of the circumstances—but “Doug owns a condo in Washington” is very different from “Doug is domiciled in Washington.” The statute itself makes that distinction.

And if the condo disappears too, the factual story gets substantially cleaner.