As per the new rules - in order to claim the child as your dependent, the child should not be providing more than 50% of his support. In your case your child is not providing his own support. So you should be able to claim him as your dependent.
Detailed explanation below-
To be claimed as a qualifying child, the person must meet following criteria:
Relationship - the person must be your child, step child, adopted child, foster child, brother or sister, or a descendant of one of these (for example, a grandchild or nephew).
Residence - for more than half the year, the person must have the same residence as you do. (More than half a year means, at minimum, six months and one day.)
Age - the person must be
Support - the person did not provide more than half of his or her own support during the year.
Nationality - be a U.S. citizen or national, or a resident of the U.S., Canada or Mexico. There is an exception for certain adopted children.
Marital status - if married, did not file a joint return for that year, unless the return is filed only as a claim for refund and no tax liability would exist for either spouse if they had filed separate returns.
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Please note: This advice is provided with the understanding that all the relevant facts have been provided by you. Any change in facts might affect the advice given and hence may not be relied on in such cases.
To meet the residency test, your child must have lived with you for more than half of the year. There are exceptions for temporary absences, children who were born or died during the year, kidnapped children, and children of divorced or separated parents.
Since your child is away due to illness, you will be covered under temporary absences and claim him as your dependent.