Ok, my buddies got back to me, he plays in U-16 for COWI and in 8 matches with them has 10 points (3+7) with 6 penalty minutes. He isnt a real big kid right now standing 184cm, 78kg but of course he will grow, and has somewhat two different styles depending on the level he plays at. U-16 he takes more risks, a little more physical, somewhat of an offensive defencemen but good puck mover. On the men's level he takes less risks and proves his age a little more. Still needs to work on his skating, bulk up some more but has good vision, discipline and puck mover.
If he is able to make it into the Latvian league I could watch him myself and give you way more information but hopefully this is good for you.

Is there any specific reason you are interested in Rastenis or just he is 15 playing in Div. I?