Can I get an insurance policy to cover someone else?

You need to have an insurable interest in the person being covered.

For certain classes of people (spouse / child), people whom you are dependent on - it is presumed there is insurable interest already. For others (your case), you need to demonstrate how the insurable interest arises at application stage.

A nice write up here (section 24.2.2) https://www.singaporelawwatch.sg/About-Singapor...

Assuming your sibling can cooperate - one way to achieve what you want is:

a. Sibling is policy owner and life assured

b. You give sibling money to pay for policy

c. Sibling does a beneficary nomination so that you will receive payout under the policy.

There is a nice FAQ/writeup linked below from insurer on the actions/considerations you need make when working through step (c)
https://faq.singlife.com/hc/en-sg/articles/1150...

Kelly is right. You will need insurable interest between the policy owner and life assured.

Though if your sibling will be both the owner and life assured and you are simply paying for him/her. Insurable interest is not required.

You can also do assignments if you wish to change the policy owner in the future.