Megan25 I am sorry for your loss. The matter of the insurance payout has likely been concluded...however in the event that it is still pending: If we're talking strictly about the insurance on the motorcycle and the insurance of the person that pulled out in front of your father-in-law then the payout would go to insured and/or claimaint. That would be your mother-in-law.
If there are life insurance policies then of course whoever the beneficiary is that is who would receive the benefits.