Lawns have been suffering quite a bit due to the lack of rainfall and appropriate watering.  The stress of the heat and lack of water open the door for insects and other problems.  Photos tell me a lot, so lets start with some background.  How often do you water?  About how many inches of water are you applying?  

What fertilizer is used and when was it applied?

What fungicide was used?

What insecticide was used and for what insects?

Thanks in advance and I look forward to working through this with you.. MP

All the symptoms from the photos are leading to lack of water. The closest weather station to you is around George Ranch..Evaporation is a big part of the issues we are seeing in turfgrass right now.  ETo ( evaporation) https://texaset.tamu.edu/

The amount of water evaporated Aug. 3rd - August 9th was 1.96 inches.

So in order to apply the 1", you would have had to apply close to 3 inches according to the math.  Of course the amount applied can be adjusted for soil type, root depth and mowing height.  

The amount of time of the application of water is hit or miss.  We recommend performing an irrigation audit to determine the actual amount being applied.  See my attached pdf.

Lawns should be mowed at 4 inches during the heat of the summer.  #1 shades the soil #2 increases root depth.

Let me know if you have additional questions.  MP