If I leave money to a disabled sibling instead of my own child, does a Henson trust still work the same way?

Yes — the core mechanism of a Henson trust doesn't depend on your relationship to the beneficiary. What matters for ODSP purposes is that the trustee holds absolute discretion over payments to whoever the beneficiary is, so that person has no enforceable right to demand money from the trust. A sibling, a child, a niece or nephew, or any other family member receiving ODSP can generally be protected the same way, as long as the trust is drafted with that same genuine discretionary structure.

That said, some practical details may shift depending on who the beneficiary is. You'll want to think carefully about who serves as trustee. A sibling relationship can carry different family dynamics than a parent-child one, and you may want someone other than another sibling acting alone, to avoid potential conflicts or the appearance of favouritism among family members. You should also think about what happens to any remaining trust property after your sibling's death, since that's a distinct estate planning question from the ODSP protection itself.

A lawyer can help make sure the trust language is properly adapted to your specific family situation, even though the underlying discretionary principle stays the same regardless of who benefits.