Very sad and thoughts go out to all those involved and friends and family.
The damage to the Cessna is quite something and I am amazed that the pilot managed to return to an airfield and land successfully. It shows the importance of always flying the aeroplane regardless of the situation. Interestingly I wonder what considerations would have been made in handling the Cessna. I guess any change in configuration would have brought added risk, so perhaps best of with a flapless approach etc.
I could be wrong but whenever I hear of a mid-air between a powered light aircraft and a glider it seems that survivability tends to side with the glider pilot due to the ability to bail out if required. It is quite rare for both parties involved to land safely afterwards.