If your child is easily manipulated by adult authority figures, you will have no way to protect him once he is an adult. Social workers can sometimes step in with a "take over" agenda that excludes parents and can truly harm the child.
Without guardianship, the adult child with autism is viewed as legally competent, and if any subtle coercion is used to have him sign things not in his best interest, there is little the parent can do about it.
There is really no such thing as being your child's "informal" guardian. Without legal guardianship, your ability to protect your child's best interests is not only seriously hampered but can actually be eliminated by the take over of an aggressive social worker.
We found this out the hard way and had to endure a serious and expensive fight to save our child.
Legal Guardianship by: Anonymous
I'm a parent with an autistic 21-year-old. If a child is not able to make her own decisions, and there were to be a medical need or emergency, you will have difficulty making medical decisions, due to individual being an adult. Legal issues are also a problem. The State will take over.