However, you will need your grandparent's permission, signature and your grandparent may have to answer some health questions or take a medical exam.
In order to buy life insurance on another person you need an insurable interest in that person - meaning you must rely on that person for financial support, or you may suffer some financial loss if the person were to die.
However, insurable interest does exist between spouses, siblings, parents and their children or grandchildren, business partners, and relatives, among others.
In addition, it may be easier for your grandparent to buy the life insurance and be the owner, but you pay for the life insurance, since you would be the beneficiary.
There are several highly-rated life insurance companies that offer life insurance for seniors without any health exam required, just a few health questions. For instance, Globe Life Insurance offers people age 78 and under up to $50,000 of simplified life insurance, and you can apply online for a life insurance policy in about 5 minutes.