Unfortunately diabetes can appear for no apparent reason - a friend of ours had similar to your husband, only not so dramatically - and he is a fit, slim man who looks after himself and has a healthy diet. Is there any history of diabetes in his family? I wish you and him all the best - it may take time to sort out his insulin, mine has been rather trial and error, but at any rate you know what the problem is - and it's fixable. Congratulations for driving 550 miles home, whilst worrying about your husband - not a nice experience, I should imagine. Anyway, all the best.