"Hans søster er vegetar."
Translation:His sister is vegetarian.
On a sidenote, i think you can call someone who is in a coma 'a vegetable'. You can in danish too "han er en grøntsag", it is quite slangy though.
Tak for det :) In France we use two different words, "vegetalian" meaning someone who doesn't eat any product of animal origine, and "vegan" being related to anything that come from animal exploitation (leather, wool etc) in all aspects of life. So "Vegetalian" is only about food^^