co-owners rights?

What is the name of your state? Massachusetts


My dad is co-owner of his (deseased)father's business with his two brothers. My dad actually only owns only 10 percent of the business, while both his brothers have 45 percent a piece. Just recently one of his brothers decided to retire and out of the blue one of my father's nephews was suddenly buying out my uncles 45 percent of the business. My dad says he had no clue that that was going to happen, aparently it all happened without telling him about it. So if this were to go through (which it seems likely) my father's nephew would own more of the business than my dad will. It doesant seem right to me, and possibly didnt think that this was even legal....Can someone help me!?!?!

I'm not an attorney but maybe one will jump in here and answer after this bump but I don't see a problem in this. I think his shares were his to do with as he pleased unless there was an agreement or contract between all the owners that stated it would require all their approval or a majority approval. Is there a contract or written agreement between the partners?