I suspect Qureshi was speeding since he said he was anxious to get home, but there could be other valid reasons such as expired license and registration stickers, weaving in traffic or not using turn signals when he changed lanes. Coming up with a reason to stop someone is relatively easy.
After Qureshi was pulled over Stem was doing his duty. Once the officer sees that Qureshi is sweating it does give him probable cause to check his criminal record and search for contraband since that is a symptom associated with drug usage. Stem will also claim that he misread the criminal record wrong when he said that the previous citation occurred two days ago instead of two years.
Qureshi might receive a settlement for the nuisance value of this case, but I don't believe a jury in Robertson county finding Stem guilty of harassment. Even if the verdict came back guilty he won't receive a significant settlement for mental anguish. This is about a $500-$1,000 case and I'm surprised that a lawyer would be willing to take it. Texas juries aren't that willing to award mental anguish claims unless there is serious injury and their attitude towards Qureshi will be: "Sorry, but get over it." Qureshi's does not appear like someone who will draw much sympathy from a jury and his ethnicity will work against him if he goes to trial.
Note: I'm not saying that the cop didn't harass Qureshi, but the case appears weak. If it had involved a different police officer then this story wouldn't have been reported in the news.