After dealing with police departments for many years, what happened to your father does not surprise me. To really answer all of your questions intelligently, we would love to have a consultation with you and your father or with your father. Looking forward to your call.
Your father is presumed to be innocent!!! It is up to the State to prove this case against him. They must prove he was intoxicated. In Texas, there are three ways they may prove intoxication: 1) having a blood alcohol level above .08 while driving; 2) not having the normal use of his mental faculties; 3) not having the normal use of his physical faculties. If the blood test comes back under .08 they still may forward under the other scenarios. Nevertheless, if the test comes back over .08 it does not prove that he was intoxicated at the time of driving. There are many defenses that may be applied in a case of this magnitude.
If an officer did not think your fatther was intoxicated he should not have been arrested. This would not be the first time that an officer was less than truthful. Hopefully, there was a video at the scene. If not, there should be one made at the station. Did the make him perform any field sobriety tests? How did they determine he was intoxicated. There are a lot more questions that an experienced DWI attorney would be able to explore with him.
Good luck and contact me if you have any additional questions.
If the blood test comes back showing that your father had been drinking, even if he does not reach the level of .08 (comparable to the breath test), he can still be charged. For years there was a test operator who testified that someone was "less than normal" at .03. Different people are affected in different ways - some may be intoxicated at a lower level, or higher level, than others. The .08 is just a presumptive - if a jury found that someone was .08, they can convict them based on the presumption. It may be truth that your father was not "drunk" but drunk is much more than intoxicated in most people's mind. "Loss of the normal use of your physical and/or mental faculties" is the definition of intoxication. If your dad had any alcohol whatsoever, they are going to try to blame the alcohol to raise the punishment level.