Ok, well you have two ways for him to come to the U.S.:
1) The K-3 spouse visa takes 6 to 9 months. The I-129F will cost $340 plus $420 for the I-130, and $350 for the visa processing fee. Then after he enters the U.S., you must still file the I-485 for $1070 and wait for the marriage interview about 5 to 7 months later.
2) The CR-1 visa takes about 1 year or so. The fees are $420 for the I-130, $330 for the visa processing fee, $88 for an Affidavit of Support fee. But once he enters the U.S., he enters as a Resident and he does not have to file (or pay for) an I-485 nor does he have to attend an additional interview. He just gets his green card in the mail a few weeks later.
So the K-3 is faster but generally more expensive. The CR-1 is slower, but generally cheaper. And no, there is no middle-visa that he can use to enter the U.S. while that process is pending. He will most likely have to wait outside.
Here is a link to both:
Now, I know you will have two issues. The first is the financial issue. You can resolve by by finding a Joint Sponsor. This sponsor must also file the same Affidavit of Support that you do and submit the same evidence that you still have to submit. The Joint Sponsor can be any U.S. Citizen or U.S. Lawful Permanent Resident that is over the age of 18 that makes the minimum amount. It does not have to be a family member or a household member. I'm truly sorry, but if you cannot find a Joint Sponsor, there is no way to waive that condition for him to be able to immigrate to the U.S.
The second issue is that you won't want to wait so long. Because of your condition, you can ask that the case be expedited. Here is a link:
And if that doesn't work, he can also try for a Humanitarian Parole:
Please let me know if you have additional questions and please do not forget to rate my service to you (not the state of the law) as that is the only way that I can get credit for my assistance. Even after you rate the service, I can still answer additional questions for you without additional charge. If you do rate me positively, a bonus is always appreciated. If you would like to request me in the future, just go to http://www.justanswer.com/law/expert-guillermosenmartin/. Thank you!