Why did Tecumseh, the Shawnee chief, resort to an alliance with the British?

He needed Britain's aid to avert land being ceded to French settlers in the Louisiana Purchase.

He needed Britain's aid to battle against Governor Harrison's soldiers at Prophetstown.

He needed Britain's aid to restrict American settlements from encroaching on Indian land.

He needed Britain's aid to subdue his brother Lalawethica, who had staged a coup. There's the choices

He needed Britain's aid to avert land being ceded to French settlers in the Louisiana Purchase. He needed Britain's aid to battle against Governor Harrison's soldiers at Prophetstown. He needed Britain's aid to restrict American settlements from encroaching on Indian land. He needed Britain's aid to subdue his brother Lalawethica, who had staged a coup.