You have two hurdles.
First, you can only deduct medical expenses you pay for yourself, a spouse or a dependent. You can also deduct expenses for someone who would be a dependent except for the income limit. That means, considering your parents, that you must provide more than half their total financial support.
Then second, home improvements increase the value of the home and may reduce capital gains when it is sold but are not deductible as medical expenses.
You can deduct costs that are medically necessary but that don't actually raise the value of the home. For example, the IRS recognizes that grab bars probably don't raise the value of the home, and mentions them as an example of a cost that would be a medical cost. You can also deduct the increased cost of making the home accessible due to a medical reason, compared to the cost of ordinary improvements. For example, if you get kitchen cabinets with the pull-down shelves for wheelchair access, you can claim a medical expense for the extra cost compared to standard cabinets.