I assume you mean who he leaves the property to when he dies.  Or maybe you also want to know if you can restrict his ownership in some manner.

Regarding who he leaves the property to when he dies you could consider a contract to make a will where you both agree to make wills and not to revoke or change who is to receive the property.  And create join wills.

If you want to restrict, such as real estate, you can leave him a life estate with remainder to children or who you specify.

You could also leave property to your spouse in a trust where the trustee administers the estate as you direct.

If you do an agreement, you should include a Waiver of all rights spouses havc under Mississippi law such as right to renounce, exempt property rights, etc.