The high levels of a diabetic can be lowered without medication?

Good afternoon,
My husband and I have a great uncertainty, 4 years ago my husband with 28 years of age began with vision problems and when he studied he went out with triglycerides and cholesterol in the sky and 480 in glucose, the next day without having ingested medication he had 320And he began by ingesting glucovance and strict diet, however, when he came to have up to 70 glucose levels so he decided to leave the medication and continue with a diet, after almost 4 years "normal" the visual discomfortAnd with glucometer we verified a level of 350, again Ingirio Glucovance and initially to go down but then it went down again and suspended it again, to the degree that carries days with normal diet, without discomfort and with levels of 119-140-136After food, so we don't know whether or not it is diabetic?
In your experiences, is it normal for a diabetic to lower your levels until it is normalized without having ingested medication?But on the other hand it may be that for having had those high levels 480-350 only once then is it considered diabetic?
We already have an appointment with a second doctor and we will do laboratory studies since the first one did not know how to give us a precise diagnosis but I go to you to know your opinion, thank you!

It has to see an endocrine to make a diagnosis.When these values ​​are available, diabetes are already diagnosed, but you have to study what type is to put an adequate treatment.

Totally agree with @regina!

If the doctor we will see is endocrinologist, but considering then that by those levels he already has diabetes because then can he return to his normal levels without taking medication?That is impossible to happen to a diabetic or not?

@Mercds, as @regina says, it is necessary to do a study that can define what type of diabetes is and east the right treatment ... Glucovance is metformin and is used combined with diet and exercise in the treatment of diabetesType 2, helps to stimulate its own insulin when it is altered, as in this type of patients, that explains the return of glycemia to "normal" values ​​... to maintain this situation of normal glycems could be explained byHaving managed to stimulate the pancreas, normally over time they increase the glycemia and a support treatment begins ... It can also be another type of diabetes given the age of your husband, you will tell us what the doctor tells you.Meanwhile, the best can be actually acting and not overloading the activity of the pancreas, making several meals instead of few and copious, maintaining regular physical activity, and being attentive to possible symptoms such as thirst, urinating more etc ... a hug!