Thank you for your question.
I am Dr Saha, I shall try my best to help you.
I feel he needs to be seen in a hospital or ER.
Bad sunburn can cause swelling.
But swelling of legs, pain can come from other conditions too like a clot.
Failure of heart can cause swelling of legs.
As he had heart attack in June he needs to be careful about cardiovascular effects.
I hope this information helps.
If there’s anything else I can do, please let me know.
If you are satisfied, please rate my answer as good or excellent.