Yes, you can buy a life insurance policy for your father.

As long as your father gives his permission/consent, and he can qualify for the life insurance coverage, yes you can. 

He would need to sign the application for life insurance coverage.  You would be listed as the Owner and Premium Payer of the life insurance policy.

You would want to name yourself as the beneficiary of the life insurance policy, which means upon your father's death, you would receive the death benefit from the life insurance policy.

Your father would have to meet any health requirements in order to qualify for the life insurance coverage. 

You can own a life insurance policy on anyone as long as you have an insurable interest in that person, in other words you need to have some possible financial loss resulting from the death of the insured person. Perhaps you rely on the person for some form of financial support, or you would have to pay for the person’s final expenses, funeral and burial.

If you just want life insurance to cover your father's funeral expenses, you may want to buy a funeral insurance policy on your father, which may or may not require his knowledge.