Baby is diagnosed Trisomy 18 and I have gestaional diabetes. What should I do?

I am 41, have 2 healthy children, and pregnant with a baby boy with trisomy 18.  My screening came back 1/6 chance so I had the amnio which did confirm this.  I have been taking insulin since the first day.  I know this baby will probably die before labor or right after especially since it is a boy.  Does it benefit the baby to raise my blood sugar numbers up a bit to help the baby gain weight?  Does taking insulin make me gain weight?  Does knowing this change the way I have been taking care of my diabetes.  I have been checking my numbers several times a day and watch what I eat.  I know that controlling the diabetes is always better for my health.  
I have noticed that my numbers are very good at times which is surprising.  Is that becuase of the low hormone level that came out from the amnio test?  

[Jordanna Joaquina, MS, CGC]

Fetal growth is affected by both maternal health and fetal genetic make-up. Given the complexity of the pregnancy, we recommend that you meet with a perinatologist, a physician that specializes in the care of mom and baby in high risk pregnancies.

We also recommend that you meet with a genetic counselor who can answer questions about the management of Trisomy 18 and can help coordinate the specialists who will be involved in your child's care. You can find a genetic counselor at the National Society of Genetic Counselors website or through companies like mine, AccessDNA.