Due to a medical condition we had to end a contract on a leased car. Can the fee to end the lease be deducted?

Unfortunately no. Even though this lease was ended due to medical reasons, the IRS will still consider any fees related to ending a lease of a personal use vehicle as a nondeductible expense.

However, if this is a business vehicle lease and you are self-employed, then you could claim a miscellaneous business expense on your Schedule C related to these end-of-lease fees.