If my parents were divorced after being married for 10 years and then my father remarried, if they are both now deceased are my sister an I entitled to his pension?

The best answer to your question is maybe or maybe not.  The answer will depend on the divorce agreement that your parents had and the details of the pension.  The divorce decree would set out who had what rights to the pension after the divorce.  Next, the pension program will also have its rules.  Some require a participant to name a beneficiary and allow certain rights of survivorship.  In these cases, there may be a payout or a continuation of benefits to the designated beneficiary.  However, not all pensions have a right of survivorship.  Some end on the death of the person.  To get a solid answer, you need to get a copy of your parent's divorce degree, a copy of any wills, and a copy of the pension paperwork and let a probate attorney review the agreements and programs to see what, if anything, you and your sister may be entitled to.