Visitor Visa - B2

Hello- I am wondering if someone has had any experience in guiding me in a matter. I am a US Citizen and my boyfriend lives in Spain. We met while he was visiting the US under the visa waiver program. He currently can't enter under a visa waiver to the USA because there where some apparent issues and that visa was suspended. He is working in Spain, has a company there, lives with his dad and owns an apartment, meaning he has ties there. I am legally married here in the USA and I am going through a very lengthly divorced so there is no reason for him to stay here but he did want to apply for a Visa B2. visitor for a period of 3 weeks because I am having surgery and he wanted to help me through the recovery. My surgery is scheduled for 11/14/13. He is financially able to sponsor himself and pay for his own expenses and in addition to that, I also make a good salary. What are the chances that his visa gets approved and he can come be with me during my surgery and recovery and then return home? I am able to provide a letter from my physician stating the time that I will be recovering and that is the time that he will be requesting for which is approx 3 weeks. Any advice or suggestions?

Thank you in advance.
AXM