Yes, a distribution from an inherited qualified retirement account can be reported as a Qualified Disaster Distribution to spread the tax liability over 3 years. TurboTax will automatically ask if the distribution was a Qualified Disaster Distribution when you enter the code 4 Form 1099-R received by your wife.
If the distribution was more than $100,000, be sure to indicate that only part of the distribution was a Qualified Disaster Distribution and limit the amount to the lesser of your disaster-related loss or $100,000 , whichever is less.
The assumption here is that your wife was a designated beneficiary of the qualified retirement account. I'm not sure why this distribution "could not be deferred" unless it was an RMD. If the beneficiary was a trust or the estate of the decedent, I don't think that this would be a Qualified Disaster Distribution.
