Please have your son-in-law visit this forum and read all he can. He doesn't have to join, but if he does we will be here for him every step of the way. Many of us are on insulin and a few are type 1 and very educated about their condition. Our forum members for the most part are very caring individuals who have 'been there-done that and got the T-shirt' so they are quick to share.
If he is indeed Type 1 he will need to learn how his meals affect his sugar readings and how to use the correct type of insulin at the right time. If he can change the oil in his car, change a tire or spark plugs, he can do this. It's step by step, following instructions. Hey it's waaaaay easier than doing your income tax or applying for a bank loan!
I have no insurance and I get my insulin at Sams Club. I understand that Costco has great drug prices as well. For testing supplies I went with a bigger, bulkier meter called a Prestige IQ because it came free with 300 test strips for about $104. In the long run the companies all make their money on the test strips so try to find one with inexpensive strips. (They all offer free meters but the test strips will cost you a bundle!)
Your daughter and son-in-law will need to learn nutrition and medication stuff together so be supportive and babysit or whatever they need to get the job done. Hang in there! We will be here for him.
"People are like stained glass windows: They sparkle and shine when the sun's out, but when the darkness sets in, their true beauty is revealed only if there is light within."
- Elizabeth Kubler-Ross