Any friend (regardless of the nature of the relationship) can apply to the probate court to become administrator of the estate.
If the estate is under 100,000 there is a simplified process.
As long as other relatives don't raise any objection, once he becomes the court authorized administrator he will be able to arrange for the funeral and the funeral home will pick up the body.
California courts have a lot of pre-printed forms available as well as self help resources.
You can also google california small estates for additional information.