It can be bittersweet for parents when their child announces that they want to move out. On one hand, you get the house to yourself, but on the other hand—your baby's all grown up, and where did the years go? There can be an added complexity to your child's forthcoming independence when your child has Down syndrome.
Capable of Independence
Generalization is unhelpful when considering Down syndrome in conjunction with an individual's ability to lead an independent life. It's an intellectual disability, and its effect on cognitive function will vary considerably. Some young people with Down syndrome are capable of independence (or semi-independence), whereas it will be impractical for others.
Concerns Are Understandable
When your child is clearly capable of some level of independence away from the family unit, it's understandable to have some concerns. You and your family will still function as a support network for your child, but it's unworkable for you to manage your child's new household in addition to your own. It can be beneficial for young people with an intellectual disability to live in a shared home with other young people with a comparable condition.
This doesn't mean that your child will need to live in a residential care facility, and when semi-independence is possible, your child will need a support network to assist them in daily life. Yes, you will still play an active role in your child's life, giving practical support as needed, but your child (and their roommates) may need additional assistance.
Your child will benefit from you hiring a daily home care service, and when your child has roommates with a comparable condition, this cost can be shared. This is a type of basic assistance care and is different from home healthcare assistance, where the caregiver will be required to provide medical assistance. The caregiver can assist with basic domestic tasks, essentially helping your child and their roommates to stay up to date with their obligations. This can include assisting with housework and other domestic duties, as well as assisting with any financial or bureaucratic matters. Having a caregiver visit your child's household each day ensures that they can maintain their semi-independence, which is extremely reassuring to you as a parent.
While it's certainly possible for many young people with Down syndrome to live with independence, it can be advantageous (or even necessary) for them to receive ongoing assistance to maintain their new life.