How to determine state tax for 401(k) distribution as a part-year resident?

I’m trying to help my in-laws with their taxes and I just want to make sure about something before filing. They bought a home in Texas (no state tax) in the middle of 2020, still maintaining residency in West Virginia until my father-in-law retired. Here’s the series of events:

• Both lived in West Virginia at the beginning of 2020
• They bought a home in Texas in the middle of 2020
  • To make a down payment, my father-in-law cashed out his 401(k), roughly $167,000
• My mother-in-law moved to Texas in August 2020 (homemaker, no income)
• My father-in-law remained in West Virginia until he retired, November 2020

On their 1099-R, they’ve clearly withheld Federal Taxes (Box 4, ~$33,000) but I see in Box 14 that they withheld $0.00 for state tax. When I get to the allocations for West Virginia, I’m asked for the amount of West Virginia Sourced income that was received while a resident of West Virginia, and the amount that was received while not a resident of West Virginia. One of the lines has the 401(k) distribution amount, ~$167,000, under the Federal heading with the other two fields empty (wv resident, wv non-resident).

I think the correct data here is to put the full $167,000 in one of these fields. I wanted to double-check though because this instantly raises their state taxes owed by $10,000+. This doesn’t seem unreasonable if they didn’t actually pay state tax on their 401(k) distribution, but I wanted to check here first to see if there are other things I should be considering.

I’m using TurboTax, fwiw.