Yes, if the $4400 income rule is the only reason your daughter is disqualified as a qualifying relative dependent, then you are allowed to claim her medical expenses on your tax return (on Schedule A, itemized deductions), even though you cannot claim her as a dependent (and you cannot claim her educational expenses).
I misunderstood your description of her support sources* to mean that you did not provide more than half her support.
*Note: SSDI, loans (that you did not co-sign), her earned income, scholarships, and grandpa's 529 are all support sources not provided by you.
