Is it permissible for me to drive my friend's wife to the hospital or airport if her husband has had an accident in a foreign country and she doesn't know anyone?

It is preferable for a wife to be accompanied by another person when visiting her husband's friend who has had an accident, to avoid unlawful seclusion (khalwa). However, if there is an urgent necessity and seclusion cannot be avoided, it is permissible, as evidenced by the story of Safwan ibn Al-Mu'attal with Aisha, may Allah be pleased with her, when he carried her on his camel to rejoin her with the army, and neither Allah nor the Prophet, peace be upon him, censured him for that.