in Indiana, what happens when my father-in-law dies with no will and no Power of attorney legally assigned?

If a person dies without a Will, then the Indiana Probate Code has a default distribution scheme. Unfortunately, as a son in law (not by blood) you will not receive any inheritance. The most common distribution for a person who passes away married with children is that the surviving spouse inherits half and the children inherit half. Special rules apply to second spouses who have no children with the decedent. Special rules also apply where the decedent had no children.