1) First, the payment from the life insurance is governed by the terms of the policy, specifically who/what is made out as beneficiary. If the policy lists your sister-in-law as a beneficiary, she gets the appropriate share; if the policy does NOT list her as a beneficiary, then the insurer literally cannot pay any portion directly to her.2) If the proceeds are going to the estate, then from the estate, they will pass according to the will. You need to reference the will to see what, if any, distribution your sister will get. Her wishes--and yours--mean nothing in this context; the language of the will controls. Of course, that language is not always clear cut or unambiguous; if it is susceptible of more than one interpretation, you may need to go to court to sort it out.