husbands loyalty is to his brother and not his self or me what should i do?

my husband is 52 yrs old and has been working for his brother for 18 yrs with no chance of advancement and no retirement benefits. my husband is very talented in his profession. i have started the same business and done extremly well.i have informed my husband he could make triple the income on his own so we could have a better future and pay off debt,but he refuses to leave his brother.hes says his brother needs him, but what about us? am i being unreasonable ? i really need to understand if i'm wrong or him. thank you for your time in this matter.