They are in fact doing rolling "brownouts" as of a few days ago. I put it in quotes because the friend who told us about it had been without for a couple hours at that point.
Rolling blackouts would be documented here if they were happening: https://www.ercot.com/services/comm/mkt_notices/opsmessages
More info: https://www.kxan.com/news/texas/do-you-know-the-difference-b...