Family Based Greencard

I applied for the green card through marriage and after waiting for six months, i got a letter from USCIS that my joint sponsor's annual income is below 125% of the poverty guideline but in the tax return papers where he showed $45,012 which is more than enough because he has 2 children and wife and the amount for 4 people in the family along with me which is 5 people altogether, he has to show around $37,700 for sponsoring me. I have talked with so many people regarding this issue and i am getting different opinions from different people. He showed in the IRS tax return transcript that his income from the business is $20,384 and the other $25,000 is from the rent of his properties. In the I-864 form, I mentioned him as a business owner and I submitted employment letter regarding his business, from where he showed his annual income $20,384 but I didn't send any papers regarding his properties. So , Is this the reason to deny my sponsor for showing annual income from the business of $20,384, even though his annual income from all sources is $45,013? if its the reason, then what do I have to submit for the other $25,000, which is coming from the rent of his owned apartments?