HI, thanks for using healthcare magic
Burns can sometimes cause significant discomfort.
The area involved should be dressing daily and an antibacterial cream should be applied.
The most commonly used cream is silver sulfadiazine
but if he is allergic to sulphur he can consider other creams such as polysporin
If the area is extensive or you are uncomfortable with the dressings then it would be best for them to be done by a doctor or nurse.
In terms of pain management, he may want to consider the use of anti inflammatory pain killers such as ibuprofen
, aspirin. These should be taken on a full stomach.
Since the area is painful, he may restrict his movement and because of this restriction, increase the risk of the DVT.
During the flight, he must remember to move around as much as he can.
I hope this helps