Property dispute brother cheated asked us to renew agreement

I and friend has started a small business of mobile sale and service. I have my youngest Brother named Rajib Sahni he was sitting at home, so i have asked him to look after the shop as we ( I and my friend) were unable give full time in shop because of our job in mobile sale after service company, and we said to him (to brother) that what ever that profit will be in the month end we will divide equally between three, he agreed. in every year end we use sit and calculated the profit and share the same, we all are haapy. but the problem arise from the year 2015 when we unable to give any time to our shop, because my was having cancer and my wife was also pregnant and my friend was also busy with job works, so in the means time our rent agreement of going to over, so my brother ask us to renew agreement, as i were busy we manage by his own and what ever necessary, but i also said that our commitment will be the same about profit share. so he agreed a