I am considering removing one of my sons as beneficiary on my life insurance policy as his girlfriend is rude, undeserving and she's made several remarks about "getting her hands on the money" what can I do to protect the proceeds for him?

You change the beneficiary or beneficiaries and leave him out.

A Will is somewhat more complicated and it depends on the State.

The money from a life insurance policy goes to the person or persons named as beneficiary. So if he is removed but the others are left listed, they get the money and he will not have any claim to it.

A will as noted is harder, and you will need a local attorney if you have a large estate and you don't what one of the children not to receive anything ( or much)

The only possible thing you might be able to do is setup a trust in your son's name. Make the trust the beneficiary of your policy. Then appoint a trustee who can manage the trust and dole out money as needed.

Or you can just remove him as a beneficiary and he gets nothing from the policy.