As long as you have an insurable interest you can buy a life insurance policy on another person.  That interest need only be present at the time you purchase the life insurance policy.  If that interest ceases you can still own the life insurance policy on the other person's life. 

In addition, you may need the person you want to insure to sign the application for life insurance and answer some health questions.

There are many scenarios where this is practiced and generally is...