Yes, you may be able to buy a life insurance policy on your brother if you have an 'insurable interest" in your brother.

Insurable Interest means that there is some sort of financial link between you and your brother. Either you rely on him for some financial support, or you may suffer financially if he were to die.

Your brother would, of course, need to cooperate in the process, sign the application for life insurance and provide medical information.  There are many circumstan...