You tear ligaments in a high ankle sprain, so yes, there was ligament damage. Lol But no surgery for that damage which means it wasnt serious ligament damage and will heal on there own and with PT.
https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=134&contentid=504
"Severe injury can pull or tear these ligaments out of place. This creates an abnormal space between 1 or more of the bones. The ligaments are very strong and don't pull away or tear easily. Ankle dislocations often occur along with a break in 1 or more of the ankle bones. In some cases, an ankle dislocation can happen without a break in the ankle bones. In these cases, the ankle dislocation occurs along with a severe ankle sprain. A severe sprain is when the ligaments are torn."
http://www.southfloridasportsmedicine.com/ankle-ligament-injuries.html
"Complete tears of the main ligament (ATFL-anterior talofibular ligament) are usually accompanied by more pain, difficulty weightbearing, swelling and discoloration to the outside of the ankle. These ligament injuries require immobilization to allow the ligament to heal primarily. In most cases a hard weightbearing cast or an ankle brace and a boot is all that is necessary. Patients can immediately weightbear as pain allows. The ankle brace should again be used in the nighttime while the patient sleeps and the boot should be used any time the patient weightbears. If it occurs on the right ankle, the boot can come off while the patient drives but the brace should remain on at all times. Immobilization may be necessary for four weeks. No anti-inflammatories should be used at any time. Physical therapy is usually begun once stability begins to take hold in the ankle and that could take 2-3 weeks. Physical therapy’s aim is to restore range of motion, strength and stability back to the ankle. Return to sports may take 4-6 weeks. These injuries are often accompanied by a mild stretch or partial tear to the secondary ligament on the outside of the ankle called the calcaneal fibular ligament (CFL). If present, similar protocol is needed. This partial ligament tear will heal in the same timeframe as the main ligament injury."
He will be fine.