Can I own a business without losing my Social Security disability payments and Medicare coverage?

My companion and I bought 50% of a small business. We put our half in his name thinking I could lose my monthly disability payments and my medicare coverage. (We didn't seek any legal advice at the time as we didn't forsee any problems!) The man who bought the other half of the business NOW feels, after almost 2 yrs, that since my name is not on the licenses, etc., I should NO say in any part of the running of the business. We did not have this problem with the previous owners, but have been blindsided by this one. I cannot afford to lose my disability payments, or my Medicare coverage as I am under 65, and suffer from a disability that requires much needed medical attention. The simple solution would be to add my name to the business, if possible. Is it? Please advise! Thank you!! - Is this your question? Add additional information