So from your description:
Breathing - does he get recurrent chest infections/need an inhaler/have shortness of breath? Probably no needs if none of the above.
Food - have you got significant unintended weight loss? Otherwise sounds like it would be moderate to me. I had to have a big argument about this because they argued because his weight had stabilised at a BMI of 14 it was no longer high. They did give in in the end.
Continence - probably moderate I think from your description.
Skin - anywhere from moderate to severe. I'd focus on this because it may be key to getting finding.
Mobility - I would guess high but this is another where severe is an option so see what you think.
Communication - I would guess high from your description? There's no severe option here.
Psychological and emotional needs - this was another one where I ended up having to have a fight. He has become less able to vocalise so their assumption was that that meant he was less distressed. I thought it meant he just wasn't even able to scream any longer. Not sure on this from your description.
Cognition - I think this one sounds like it should come out as high or severe. Severe is probably what you need to push for to have some chance of CHC funding.
Behaviour - this is where we originally got the second severe that compelled CHC funding and as he became less mobile the risk level came down. Make sure you flag areas where there may be a risk to others if they exist.
Drug therapies - this is going to depend how brittle his diabetes is and how challenging it is to manage. Is he type 1 or type 2? Does he need injections if insulin etc.
ASC - none that you've flagged I don't think?
Other needs - we accepted this as none and it was then flagged as evidence for why he didn't need CHC later so worth considering if there's anything extra you might find it helpful to bring in here.