Her laptop will most likely be fine, all recent laptops have universal converter/ac adapters that will work on any voltage between 100-240V and 50-60Hz. For her iron she probably will need a step down converter, or a converter that steps the voltage down from 220V to 120V (unless her hairdryer has a dual voltage switch). If the iron is 120V only, she needs to buy a converter that will handle the high wattage that irons use and check to be sure the wattage of any converter she buys has a wattage rating at least as high as the wattage used by the iron. It might be just as cheap to buy an inexpensive iron there in Thailand and she shouldn’t have to worry about a plug adapter as well.
I’m sure you know that the US uses either the two flat blade or two flat blade with round ground pin type of plugs. The plugs in my house accept both of the US type plugs and the two round pin or European type of plugs often used in Thailand. I always keep a two round pin plug adapter and a two flat blade adapter around for when I travel around the country and that’s all I ever need.