Yes, this Oklahoma DUI though out of state will likely affect your husband's Texas driver's license.
The Texas Department of Public Safety (DPS) may suspend a person's license upon receipt of a notice of conviction of an offense committed in another state that, if committed in state, would be grounds for suspension according to Texas Transportation Code 521.306, 37 Texas Administrative Code 15.82.
If you are convicted of a DUI / DWI in another state, the state will report the conviction to Texas. If you have a commercial driver's license (CDL) based on Texas law, TX DPS will suspend your CDL for one year, and for life upon a second conviction.
So it would appear that even though the DUI took place out of state the penalty for getting DUI in the state of Texas will apply. Texas Transportation Law section 522.081 gives information on how a CDL holder can get their license disqualified. Under subsection B it notes that a person who holds a commercial driver's license is disqualified from driving a commercial motor vehicle for one year for a first conviction of driving a motor vehicle under the influence of alcohol or a controlled substance.
Subsection C goes on to say that a person is disqualified from driving a commercial motor vehicle for life if the person is convicted two or more times of an offense specified by Subsection B.
Your husband can contact the TX DPS to get specific information on how this OK DUI will affect his Texas CDL.