It sounds as though your father, and your family, have been through a lot over the past 2 years. The diseases which you mention are very difficult to deal with, as you likely already realize. It is not uncommon to see people at tertiary care centers (referral hospitals) with these diseases in combination, and when multiple of these are present, as in your father's case, it does increase the risk of further co-morbid conditions developing, such as the recent stroke.
Based on what you present here, it sounds as though multiple physicians in multiple specialties need to be involved in your father's care, and coordinating as much as possible his therapies, tests, and long-term outlook. For his care, he needs a cardiologist (may consider one who is specifically trained in heart failure given your father's severely reduced heart function), nephrologist (for possible dialysis or monitoring), neurologist (for recent stroke), and endocrinologist (for optimal diabetic control, as stringent control reduces rates and risk of complications). Further physicians may be necessary based on what is found from your father's history and current health state. These things, given his severe condition currently, would best be handled at a tertiary referral center, which may be a regional center, or located in a major city near you. If you are not at one of those centers already, consider seeking referral to one. If you are already at a tertiary center, and are frustrated by lack of communication and care, then I would first recommend discussing with your father's team first to bring up your concerns and see if they can be rectified. If they are not able to be fixed, or are met with difficulty, then you can consider a second opinion at another advanced center to see if you get the more cooperative and desirable environment you and your family desire.
Another suggestion: We can cure and prevent the diabetes easily by following the 2 below simple steps. Many diabetic patients followed these steps and found great improvement in sugar level.
1. We need to chew the food very well. When you chew it, teeth grind the food well and it will become semi liquid shape with saliva. We need to taste the food while chewing so more saliva will form that will surround the ground food. After the food has become semi liquid shape only, we need to swallow the food.
2. We shouldn't open the mouth while chewing until we swallow the food