How frequent are alcohol withdrawal seizures for a person who drinks two times a week but gets drunk?

See below. I am not worried about seizures but I am worried that you continue to drink while you are concerned about consequences.
Not to be expected. This pattern of alcohol consumption would not be expected to result in seizures during absence of alcohol, unless of course you are misinterpreting your frequency of usage. Please do not drive on days when you use alcohol. Police are artful overachievers when it comes to alcohol and marijuana.
Not very high. Alcohol withdrawal seizures occur in drinkers who really are addicted to alcohol and have fairly constant levels in their bodies. Sporadic alcohol binges may however increase seizure risk at the time, but the full blown withdrawal with dt's would be far less frequent.