I was wondering if there are any primary sources in which an enslaved individual negotiates the terms of their bondage using the concept of disability to their advantage? Additionally, could the concept of disability be used to resist work, keep familial ties, or negotiate the terms of bondage? I was reading my professor’s dissertation on slavery and noticed that on different plantations throughout Virginia during the 19th century, some enslaved people were sold for $0 if they were above the age of 40. I would infer that meant they had some sort of disability or impairment which inhibited them from working. It led me to think of this.
On the contrary, disability usually meant worse conditions for enslaved people in America, not better. While many disabled slaves could and did work, those who could not were more likely to be mistreated, abused, abandoned, and killed.
Leslie Howard Owens's book This Species of Property refers to enslaved disabled and elderly people being sent into the woods to live alone, with no means of supporting themselves; they were barely given food and often only had one set of clothes. Emily Burke's Pleasure and Pain describes an asylum in Georgia where abandoned disabled slaves gathered; they were manumitted so that their enslaver didn't have to care for them, and left to fend for themselves.
Dea Boster's article "Useless": Disability, Slave Labor, and Contradiction on Antebellum Southern Plantations has a number of other similar stories, including enslavers murdering disabled slaves, often due to not performing work adequately.
There's also a Wikipedia article on disability in American slavery with some additional sources for you - but the literature pretty much universally points to disability being a hardship for enslaved people. This does not mean there are no examples of disability being used advantageously - Ellen Craft employed it as part of her escape with her husband, and Harriet Tubman was struck in the head by her enslaver as a child, causing a traumatic brain injury that affected her greatly and is thought to have been part of the reason she escaped initially. According to Sarah Hopkins Bradford's biography of Tubman, she was afraid she would be sold for being an inadequate worker, and decided to escape instead.
So disability was absolutely significant in the lives of many enslaved people, but there do not seem to be any sources that it was used as a negotiating tactic or means of resistance. Even in Tubman's case, it may have prompted her resistance, but she didn't ask "hey, I'm pretty bad at this work thing, can I go now?" This is not to say that slaves did not negotiate - indeed, the experience of chattel slavery was often negotiated, with Harriet Jacobs as a notable example - but I have not heard of primary sources regarding disability being a negotiating tactic.