DLA does not exist unless you are under 16. It's PIP for Adults and it's not the condition you have it's the affect it has on you.
Having diabetes does not make you disabled so don't ever think it does. If you have complications then you can apply for PIP but no guarantee you will get it.
The country would be bankrupt even more than it is if people with diabetes were given benefits.
In my experience your refused if your diabetic. Out right.
If you have other problems which stem from the diabetes they are noted.
Being blind or limbs missing still not enough to stop some people from working.
Very few cases are being successful, currently. Kicking people off benefits not taking new claimants unless forced to.
If you need financial support through illness don't expect this government to help. Burden on employers instead. Not matter how much tax you've paid all your life.
I pity new bosses who have to pick up the governments inability to support tax payers when they need it most.