While food and housing costs are included in support, the only potentially deductible expenses you've listed are medical and dental expenses.
Determining who can deduct your parent's medical expenses is a bit tricky because several people are helping provide support. Generally, the person who claims your parent as a dependent gets to deduct these expenses. If your parent isn't claimed as a dependent by someone else, the person who provides more than 50% of their support gets to deduct the medical expenses. If no one provides more than 50% of your parent's support, the person for whom your parent is otherwise a qualifying relative may be able to claim your parent as a dependent on their tax return. To do this, that person must have provided more than 10% of your parent's support and anyone else who provided 10% or more must sign a multiple support declaration (Form 2120) to waive their rights to claim your parent.
For more information, please see Steps to Claiming an Elderly Parent as a Dependent and About Form 2120, Multiple Support Declaration.