Agreed with Andy that more information is needed. Here's a bit of additional context that may be helpful to you:
Social Security Disability Income (SSDI), Social Security (SS), and Medicare are all entitlement-based programs. That means, if you meet the requirements and have been approved by the government agency, you are entitled to receive the benefits.
The level of assets and "unearned" income (non-employment income such as interest, dividends, or capital gains on sale of stock) are not considered by the government agency for entitlement programs such as SSDI.
Medicaid and Supplemental Security Income (SSI), on the other hand, are needs-based programs. That means you must meet the program's definition of "need," which usually means you must spend-down assets such as savings/investments. There are also limitations on the income you can receive, regardless of whether that income comes from employment or is "unearned" (interest, dividends, capital gains, etc.).
Coming full circle now . . . IF you only receive Social Security Disability Income (SSDI) and are NOT also receiving any Needs-Based assistance, then typically the sale of stock would have no impact on your benefits.
We are going to need some more information on your question before we know how to answer. Is this stock you received as stock options with an employer? Or are you looking to sell stock you bought in a personal account?