But the problem with tobesky is that his English is not that good. So I think he will find it difficult to free write, most of the time he will just struggle finding the right words to use.
I agree with Llamapoop123, you need to think what you like first. You can do this in the language you feel most comfortable with. The problem here is not that you can't write something out, is that you're not even sure what you want. Start with that!
Right. While it's not a good idea to compose an essay in your first language and then translate, preliminary tasks such as free-writing or brainstorming can be done in whatever language one feels most comfortable.