Should he take a riba-based loan to get medical treatment for his son?
Question

                There is a man who has thirty thousand riyals, and he has a son who is sick. The doctors have decided to do an operation for him which will cost sixty thousand riyals. He could not find anyone to lend him the outstanding amount, and he could not find any other way, so he invested the thirty thousand riyals in riba and got sixty thousand riyals, and had his son treated, and he is saying that necessity makes forbidden things permissible. What is the ruling on that?.
Praise be to Allah.
    He has to repent to Allaah for having dealt in riba, because 
    need does not make riba-based transactions permissible, and such cases are 
    not described as necessity, because treating the sick is mustahabb and not 
    obligatory, and because he could have borrowed the money or bought something 
    on credit then sold it for immediate payment that was less than the credit 
    price, or other means of helping himself to meet his need. We ask Allaah to 
    help us and him to repent sincerely. And Allaah is the source of strength.