Q: My 10-year-old son has autism and will need care the rest of his life. This has put quite an emotional and financial strain on my husband and me. His parents and mine are willing to help but we've heard it's not a good idea to put our son in their will because it might affect his ability to qualify for financial aid. Can you shed light on this?

A: First, a word of encouragement: You are not alone, and many support groups and resources exist to help you.

According to the U.S. Centers for Disease Control and Prevention in Atlanta, about 560,000 people under age 21 suffer from autism spectrum disorders in the United States. The most recent figures I've seen, from a study released by Yale University last year, indicate the average health-care expenditures for a child with autism or related disorder were almost $6,000 in 2004.

In addition, other disabilities such as cerebral palsy and Down syndrome disrupt family lives and finances.

As to your question, experts recommend keeping assets from going directly to a child with disabilities. If a person with a disability or special needs owns or inherits property above a certain dollar value — generally $2,000 — it could make him or her ineligible for certain government programs, such as Supplemental Security Income and Medicaid.

''The government doesn't go out and advertise it. A lot of times families are not aware of that fact,'' said Joe Eppy, a special care planner in Florida with the MassMutual SpecialCare program, which assists people with disabilities and other special needs, and their families.

A better solution, experts in the field say, is to set up a special-needs or supplementary-needs trust that allows families to safeguard the child's eligibility for benefits while also providing for additional needs not covered by government programs.

Understandably, for many families dealing with the day-to-day struggles of caring for a disabled child ''the last thing in their minds is planning for the future,'' said Joanne Gruszkos, founder of the MassMutual program.

But it is important for parents to take the right steps to make sure their child is cared for after they die. That's particularly the case with autistic children: People with autism tend to have a longer than normal life expectancy, Gruszkos said, and therefore will need care longer.

Easter Seals, which offers services to people with disabilities and their families, recommends that, in addition to setting up a special-needs trust, parents of disabled children draft a ''letter of intent.'' This letter, while not legally binding, provides a guide for the child's caregivers or the courts on how the parents would like the child to live after they die.

With Open Arms, an informative 72-page guide by Easter Seals and the National Endowment for Financial Education, includes a worksheet to help parents begin writing such a letter. A free downloadable version of the guide is available from the Easter Seals Web site, at http://www.easter-seals.org (you must first sign up as a registered user of the site). A printed copy can be ordered by sending a $5 check for shipping and handling, payable to Easter Seals, to With Open Arms/Easter Seals, 230 W. Monroe, Suite 1800, Chicago, IL 60606.

The printed guide can also be ordered free from the MassMutual SpecialCare site, http://www.massmutual.com/scresources. Parents and caregivers can also request a free compact disk containing a fillable Word document template for a letter of intent. Also available are a 208-page resource guide and a 64-page ''Making Plans'' guide for people with Down syndrome and their families.