How is it that a federal judge, a member of the “co-equal” judiciary branch, has the power to issue any ruling whatsoever on an order issued by the co-equal president or on a law passed by congress and signed by the president?
How is it that an un-elected person is more co-equal than the other two branches of government?
Can a president overturn a judge’s ruling? No.
Can the congress overturn a judges ruling? No.
How is it that a judge can do anything other than apply the law as written on a case that happens to be before his court?
It seems to me that the un-elected branch of government has considerably more power than both of the elected branches combined.
That's what they are doing, although not always correctly. Remember, the constitution also counts as "the law as written".
Not correct.
Congress passes laws, judges interpret laws constitutionally.
If a judge overturns a law congress can pass modified legislation that corrects the grounds for the judge's decision.