As to any contingent remainder or executory or other future interest held by the slayer or elder abuser, subject to become vested in him or increased in any way for him upon the condition of the death of the decedent or victim:
(1) If the interest would not have become vested or increased if he had predeceased the decedent or victim, he shall be deemed to have so predeceased the decedent or victim.
(2) In any case the interest shall not be vested or increased during the period of the life expectancy of the decedent or victim.