From one discussion of such trusts:

"Is it possible that [a lawsuit-funded Special Needs] trust is not a grantor trust? Yes, barely. The key shorthand way to double-check: look for a provision that says the beneficiary's Medicaid expenses must be repaid with trust assets upon her death. If that language is in there, either the trust is a grantor trust or someone has created a really peculiar instrument. If that language is not in there, there’s actually a chance the trust is not a grantor trust — before going further with this analysis, go ask a qualified attorney or CPA whether the trust is a grantor trust."

https://elder-law.com/income-taxation-of-the-self-settled-special-needs-trust/