1. you should distinguish yourself as either a copy paste coder, or a genuinely articulate engineering guy who loves to churn original stuff.
2. if #1 is true, then you should continue to pursue coding as hobby and help your old man in putting his affairs in order by using your skill set.
3. if #2 is true then 1. are you positioning your self correctly? 2. are you reaching out to right set of hiring managers? 3. are you able to effectively communicate in your own mother tongue about your skill set? forget English, clairvoyance could be be exhibited in your language as well. 4. did you analyze why you flunked your interviews, was it communication or technology? 5. are you a guy who starts 20 different things or projects and complete very few. 6. do you have a github page to showcase your technological prowess?
After you analyse your self, ask question, why your brain is so adamant and thinking about taxes etc? could it be way to escape for not accepting that you are not a good engineer?
Your father has given you food and education with his EMPIRE and he is still running it successfully, i would say since he is still supporting you.
Very few of us are luck to have old man setup a running business, if you are not doing any thing right now, sit with him, help him in optimizing his business with your skills, trust me in bad days 1 in hand is better then 2 in bush. Ask him to pay you salary for your time so that you feel independent and lookout for good opportunities simultaneously.