Hi Alice, we often get people joining here who are now adults but were diagnosed as children and what seems to happen quite frequently is that they have been somewhat overlooked by the healthcare system. By that I mean that maybe it is assumed by the doctors and nurses that they must know everything so they are just left to muddle along as best they can.
The good news though is that treatments and knowledge are improving all the time, so much better control is possible and it doesn't have to be that hard to achieve. The fact that your partner is on a mixed insulin suggests that he has not been told of the benefits of using two separate insulins - one for his 'background' needs, and one to take with his meals and snacks. This regime is called 'MDI', or Multiple Daily Injections - it gives much more control and flexibility with eating and can reduce the likelihood of hypos once you get it right.
I would suggest that he asks to be referred to a consultant-led clinic for a reassessment of his needs. This will also give him access to a fully-qualified Diabetes Specialist Nurse (DSN) - most of them really know their stuff and will be able to talk through the problems he is having, and should also be able to talk to as and when required.
A lot of people find it difficult to discuss their diabetes, especially if they are having problems - they may feel they are being judged or feel embarrassed by needing help. Perhaps he might like to join here himself - it can help to talk to people who know just how things are living with diabetes, which can be so difficult at times to explain to someone who doesn't have it.
I would suggest getting a copy of
Type 1 Diabetes in Children, Adolescents and Young People by Ragnar Hanas, which is packed full of information about all aspects of living with Type 1. Understanding what the options and reasons behind things are will really improve his chances of getting better control.
Please ask any questions you may have, and I hope the GP appointment goes well
🙂