Immigrationboards.com

My father needs some help but his English is not very good so he asked me to post his question. He is a Bulgarian citizen who has been living in England. He has a job offer at the moment but doesn't have a visa. He is thinking of getter a self-employed visa. Any ideas what documents he needs to get it? His other idea is to show he is self-sufficient. How much money does he have to show that he has? Can I sponsor him? I am a Bulgarian citizen living in the US. What documents do I need to sponsor him?

Thanks so much for any idea.