West Midlands GP Dr Stuart Gray and his brother Rory have also hit out at a EUR7,500 compensation payment to the locum, Dr Daniel Ubani.
The Grays, whose father David was given 10 times the recommended dose of diamorphine by Dr Ubani, discovered the payment after preparing a case for the European Court of Human Rights (ECHR).
A ruling by the High Administrative Court of the State of North Rhine-Westfalia that Mr Gray's death in 2008 was only 'partly caused' by Dr Ubani led to him receiving a payment of EUR7,500, including costs.
Dr Ubani claimed the German regulator's bid to hold a fitness to practise hearing violated his right to employment under the German constitution.
The ruling came after he was struck off by the GMC and a British coroner ruled that Mr Gray had died unlawfully.
'Numb with shock'
Rory Gray, who lives in Germany, said: 'I am numb with shock to have received the documents which show the payment was made because the technical discussion by the doctors' chamber infringed Ubani's constitutional right to practise his profession.'
Now the brothers have lodged a case with the ECHR against the UK and German governments for infringement of five articles of the human rights convention. They include the right to life and the right to an effective remedy.
Dr Gray said: 'The EU put the doctor's freedom to travel and data protection above patient safety. It is frustrating and makes me angry.
'Ubani is still practising in Germany. The local council, which has the authority to do so, has not restricted his licence.'
His brother said: 'We have had to pay to instruct lawyers in both countries, to try to obtain whatever scraps of information they are able to.'
Last week, the House of Lords was preparing to debate a motion on the mobility of EU health professionals.