Good post I enjoyed reading it but some of the information within it just isn't accurate.

Firstly there are more than 2 types of Diabetes the 5 main sub types include

Type1,
Type2,
Maturity onset diabetes in Youth (MODY) type 2 for kids
Latent Autoimmune diabetes in Adults (LADA) type 1 for adults and
gestational diabetes.

The only reason that a type 2 would really need to have any medication is if they plan on having a highly laden plate of carbohydrates which will cause a massive spike in blood sugars, whereas type 1 who obviously have no insulin to naturally lower the blood sugar, require both to act against the carbohydrates they consume but also for their protein consumption due to the production of sugar through the breakdown of proteins and amino acids into sugar through gluconeogenesis. Therefore eating a high protein diet for type 1 could be as detrimental as eating high carbohydrates.

As far as calories are concerned it couldn't be further from the truth both protein and carbohydrates both have 4 calories per gram and Fats have 9 calories per gram.

Obesity amongst other things is due to Insulin resistance, and carbohydrate intolerance, and therefore when the body cannot process the excessive amounts of sugar in the body it converts into triglycerides and stores it within the adipose tissue. and you are correct it is the Insulin resistance that causes Type 2 diabetes.
Eating fat doesn't make you fat unless you consume too much of it.

The growing body of evidence within the medical field supports the fact, and has been published in some of the biggest medical journals that you can reverse type 2 diabetes to pre diabetic states if you follow a low carbohydrate program.

it should also be noted if you are type 1 you needn't feel despondent their are many good programs designed to allow you to have normal blood sugars without injecting yourself with vast amounts of insulin on a daily basis for example Dr Bernstein's Diabetes Solution. He himself is a physician and diabetic for over 70 years now and lives a very active and happy life without the chronic complication associated with diabetes.

I wish your parents well and hope they can manage to prevent the development of the chronic complications associated with diabetes.