Children actually get SSI, not SSDI, and the amount received is based on parent's income. Check on the social security website, but I suspect if your income is too high for medicaid, it's probably too high for SSI. Daisy receives SSI for another medical condition, our total income is less than 1000/month, and she receives less than 100/month in SSI.
As far as it affecting his future, no, it won't. Never have I been questioned about Daisy's SSI in the past 11 years.