My sister's husband impregnated a girl..

My sister's husband impregnated a girl she gave to a baby boy.He lived with the girl but did not marry her untill she died,he then paid her bride price after her death . He then married my sister and they did both weeding and traditional. And this annoyed the mother of the late wife,that she went about complaning to people saying that my inlaw did not marry her daugther and does it mean that her daugther is not worthy of getting married to, and because of that my sister will never give birth to any child and carry the child. that any of her child that falls sick if she administer any treatment to any they will die. and ever since then, each time my sister gave birth once the child is a year and six month the child wil die after minor illnes and these children are all male now she has given birth to the third a male also which is just three weeks old. please i want the house to cover this innocent child wiith prayers to destory every evil trape that has been set against him and otther unborn.