You have a child with special needs. You provide support and assistance right now, but you are very conscious of the fact that your child will need extra help when you pass away. You're considering leaving them the bulk of your money in your will, knowing your other children will understand.
This is a noble goal, but you need to make sure that you go about it the right way. Mistakes made during this process could do more harm than you realize.
For instance, your child may be able to get financial assistance from the government. This may include things like subsidized housing, vocational rehabilitation, Medicaid and Supplemental Security Income (SSI).
Part of the reason that they qualify, though, is that they have no income and no assets of their own. If you leave yours to them, you may accidentally disqualify them from these programs. This means the government will neglect to give them any assistance until they spend your assets. At that point, they'll have to apply.
You likely want to leave them your assets in addition to government assistance, raising their quality of life. One way to do this is to put the assets into a special needs trust, rather than your will. Your heir may then have access to the money without technically owning it, allowing them to get government assistance as well.
Clearly, this is a complex process that can get pretty technical. You do not want to make a critical mistake. Make sure you carefully consider all of your legal options while deciding what to do.