@jmwalker1 and to be your dependent, since she is a close blood relative, there is no requirement that she live with you. So in this instance, as long as you provided more than 50% of her financial support during the year, she is your dependent for the purpose of deducting the medical expenses on your tax return.
Note that only the expenses that exceed 7.5% of YOUR income are deductible and you would have to itemize for it to have any value.
Despite what the 'expert' states, there is no requirement that you provide all her expenses for half the year. Rather, it's the opposite - you provide at least 50% of her expenses over the course of the tax year.
