That is a chemistry thing. Hydrogen and carbon can form very very long molecular chains which have very special functions. At some point we call this things life. With helium you simply can't do this.
I allways hated chemistry so maybe someone has a better knowledge about this.
I don't know if it is possible to make large moleculs with somethings different, but i think it is not possible, otherwise we would have found some other type of lifeforms.
Living without water-> i think this is impossible
Living without oxygen-> probably yes, there are some germs which life near volcanos underwater which don't need oxygen or sunlight.