Yes, it will be a bit difficult as your lungs have reduced its capacity. Try working out daily for an hour (endurance exercises/ breathing exercises like- walking, jogging, swimming, skipping, running, etc) as much as you can.
Preventing heart attack and preventing diabetes requires same strategy. They are caused by glucose. Discuss diet with an intelligent MSc biochemistry, that is the best way to get scientific information.
Yes, it is ok but why you give Poha all the time? You can give oats, dalia (if diabetic then you can give only namkeen dalia otherwise you can give both namkeen or sweet porridge. And also you can give double tinned milk if not available then when boil the milk mix 1/3 portion of water and can consume. Sauted vegetables. Etc. Low fat and reduce salt intake then normal atleast one portion of normal salt, and never use raw salt. Use fibrous food more in daily diet. And sprinkle with cinnamon powder, jeera power, black pepper powder etc. You can use Lemon dressing.
And try to take food early.
few tips on diet - say no to maida items like toast , khaari ,naan ,white bread . can drink tea but without sugar and say no to Buffalo milk and can drink cows milk , can eat brown bread , can eat sprout’s , can eat green vegetables, can eat chappati ,bajra ka rotla can eat one katori of rice twice a day with dal and to avoid farsan food items and can eat fruits and say no to coconut water