The bond between twins is very outstanding, almost nothing can break this bond. Twins lose each other in many ways. So, there maybe more Twinless Twins out there. Living with out a twin can be very hard for a lone twin to deal.
Twin grief is very different due to the bond that had developed while womb.
We do our best in helping twins to cope with the loss a twin. There is also a Twinless Twin Conference held each year. When this happens, the body reabsorbs the fetus that died or the other fetus absorbs its. We have found no info on why or how it happens, its still a mystery to us. You cannot grieve alone.