Hello, Thanks for writing your query to us. Thats very lucky that he did not have any injury after having such major accident, but then also i would advise you to take him to hospital. Even though there is no external injury but some blunt trauma can give rise to internal injury. Injuried tissue cells release chemicals that causes inflammation called as chemical mediators of inflammation. This increases temperature set point & this leads to activation of heat generating mechanism which gives rise to fever. The cause of fever can be infection of any type bacterial, fungal, viral or trauma or exposure to an allergen So kindly take your husband to hospital for detailed evaluation. Take care.