He is not the older brother. That's just his personality hashirama is an easy going person and tobirama isn't. He was stating the truth at that time that's y hashirama kept quite.
clearly because hashirama's role was a big part of the bringing people together aspect while tobirama is better to straighten out broken parts of the system politically while being very powerful. plus everything was about power back in those days and clearly hashirama>tobirama as far as power.