I Sure Hope So, The Doctor Changed My Friend's Insulin

I sure hope so, The doctor changed my friend's insulin to invokana, he is still losing weight. Now he is in the bed sick after the flu shot. But, he was having problem with the new medicine, which he has lost 13 pds. with the change. Now he is sleeping & we have to wake him up & he may eat a bite or two & back to sleep. Made him go to to his doctor yesterday she said get him to the emergency room now. The doctor there said the shot made him have flu like systems & sent him home. He is still sleeping & sugar reading was 200.So, should we wait as the second doctor said on the shot to run it's course or his doctor & see someone else ?? Thank you Doris Rogers Williams