To the best of my knowledge that disability income is to be used to provide needed assistance of your child. If it is not needed for that purpose at this time, you should be allowed and able to bank the money for use of needed care in the future. The money is owed to and given to you and or your child for that purpose, to provide and care for them. I don't believe there is any law that says that you can't bank the money now and use it as needed as long as you keep records and can account for the dispersal of such funds.
Just my thoughts, check with an attorney in your area, cost should be minimal compared to the peace of mind you will gain. 