In order to buy life insurance on someone else you need an "Insurable Interest" in that person, meaning you rely on the person for financial support, or stand to lose financially if the person dies.
Insurable interest does exist between parents and children, siblings, spouses, family members, and business partners, among others.
However, in order to buy life insurance on your grandparent you may need his or her permission, signature on the application for life insurance, and your grandparent may need to answer some health questions.
However, you may be able to buy senior life insurance with no exam for your grandparents.
These are simplified issue life insurance policies without any health exam required. You can get an instant quote and your grandmother's acceptance for coverage is guaranteed if she is between 45 and 85 years old.
Many children and grandchildren get life insurance on their older family members to help pay for final expenses or for estate purposes.