He is actually quite young here. Just 31 years old but like you said you can obviously see he wasn't really taking care of himself. He had put on so much weight that he became almost an obese and as you know excess weight triggers heart related problems which caused his death.
Miika was very quiet and shy around people he didn't know, not a lot of people really knew him. my dad and my friends dad used to know him. he was quite a character apparently when you got to know him better. but yes, he didn't take care of himself even tho he knew about his heart disease