Delta does not usually respond to "what if" questions. There could be endless amount of "what if" scenarios. Delta used to grant refunds or waive penalties if someone were to get sick and could get a doctor's letter stating this. Someone at Delta refunds told me that kind of ended because people would expect their doctors to write such letters. One example was addressed to Delta refunds on OBGYN stationary stating "We have examined MR Johnson and he is not able to travel due to illness". Now that most fares do not carry penalties, the biggest obstacle is the time limit to use the funds towards a new ticket (must complete travel within one year of original ticket issuance).