Property division between the brothers who decide the share

My grandfather owned a land, now we are planning to split to between my father and his brother, the land has road facility in top and bottom, now while splitting my father will get the top portion which has access to a road of 30ft, my father's brother portion will have access to a road of 15 ft. in this case do my father need to give way to his brother via our land. The width of the land in top portion is 24 ft and 30 ft in the bottom. if i have to give way how much should i give. My father's brother is forcing us to give 10ft of way, if i give 10ft in 24 ft, we can't do anything on it