Child disability payments

You will not be entitled to anything extra in your Income Support. The Income Support is money for you, not for your child. 

With lower rate care you would be entitled to the lower disabled child element of Tax credits. You will need to contact HMRC and report the changes. 

Other than that with low rate care there's nothing further you're entitled to. You won't be able to claim carers allowance for looking after him because for this he would need either mid/high rate care DLA.