Credit to my sky miles account only I can use

I booked a trip to fly to South Africa in April of this year to see my mother and celebrate her 72 birthday with her. Unfortunately I was diagnosed with colon cancer and due to the size of he mass was told I was not allowed to fly and had to have immediate surgery to remove it. I contacted Delta and explained the situation to them prior to the flight I was told there would be no issue and that the full value of the flight would be credited to my sky miles account for future travel. I underwent major surgery on on the 21st of April, the day after I was supposed to fly and am currently undergoing chemotherapy for stage 3 cancer. I am now wanting to use this value to fly my mother to USA so we can see her for Christmas she is 72 and understandably beside herself due to my health issues. I contacted Delta and to my utter dismay was told that I could only use the travel credit for me to travel. I have used my delta miles and Delta credit on many occasions over the last 8 years to fly my mother to the USA and have been as high as a Platinum member with Delta. I simply want to use the credit for the ticket to book travel through my Delta account so that I can see my mother.