Your note on the web touched me. It sounded like a cry for help from a young man struggling to stay afloat. Internet correspondence with people I don't know is not my habit but I feel a concern for you.
I am not privy to all that is in your situation.
How old are you and how long have you been a Christian?
Are both of your brothers Christians?
Does your brother who stayed home share your feelings?
On what terms was the returning brother brought into the business? Is he an employee or did he buy into the business?
Are you involved in an unequal yoke, ie. are both of your brothers believers? You could be faced with selling your interest and starting a business of your own.
How does your father see the situation? Can you appeal to him for guidance?
If you and your brother bought the business why do you still retain the irritations?
If your father has a will how can others take what is not theirs?
There is so much that I don't know but it sounds like it is time for a family conference to clear the air and redefine everybody's limits and responsibilities.
The closer we come to home the more crucial relationships become.
Have you thought of seeking advice from a wise business man in your church or community?
Above all don't become weighed down with resentment and bitterness. You need to forgive your brother and deal with him graciously. It only takes one to forgive. To forgive wrongs gives the soul buoyancy and joy.
It is a reminder that we also are forgiven by One who was offended by our sin in a way that we will never understand.