I live in the mid-cities area, which is about 10 minutes from the airport. There is a LOT of construction going on in the whole metro, so traffic does get slow. But compared to south Florida, traffic moves just fine.
I like living in the mid-cities for several reasons. It's mostly a blue collar area, which I honestly like. Not a lot of "keeping up with the Jones's". Also housing is priced reasonably. One can find a 3/2/2(older home) for around $100-120k. At the same time they can also find a 3/2/2(new home) for over $300k. I'm 20 minutes from Dallas and 20 minutes from Fort Worth. We got pretty much everything we need within 10 minutes from here. There's plenty of variety when it comes to eating out. Vietnamese, German, Italian, steak houses, etc. are all within 20 minutes from my house.
If they have a house in Seattle they can sell that house and make money coming here, buying a much larger house. The housing market is incredibly cheap in Texas compared to the rest of the country. And Dallas has a mix of it all, honestly. We got cheaper houses, normal people houses, and millionaire housing as well. Just tell them to make sure to check the property taxes before purchasing a house, as the percentages are higher in Texas versus the rest of the country.