To get at early Native American writing (like this penmanship exercise), one often has to sift through the works of white missionaries, administrators, and agents.  For instance, William Henry Kilby, who met Deacon Sockbason, wrote in his 1888 Eastport and Passamaquoddy: A Collection of Historical and Biographical Sketches:

He could read and write, though his spelling, as shown in the sample in my possession, was rather imperfect; and he had been to Washington to see the President.  He considered himself the greatest man in the tribe, and was continually trying to impress others with the idea of his dignity and importance. On special occasions, he wore a coat of startling style. Years ago, on one of my visits to Pleasant Point, looking over the fence of the little burial-ground I saw a rift of split cedar standing in place of a headstone, bearing in rude letters the inscription. (TIKN SOKEPSN)

Kilby's characterization of the phonetic spelling as “rude," and his obvious distaste for a Native man who displayed confidence or material wealth, tell us much more about the racist attitudes of the time than they do about Sockbason himself.  

The Passamaquoddy reservations in the 19th century (and later) were grievously poor, because, as the Abbe Museum explains, the state of Maine--illegally, and continually--sold off and leased tribal lands and resources without distributing the profits to Native people.  Those resources included timber, a theft routinely protested--in writing--by Passamaquoddy leaders including Deacon Sockbason, and later Lewey Mitchell, the tribal representative to the state legislature in the 1880s.  Donald Soctomah's archives include this petition from Deacon Sockbason, demanding that the State stop depleting fish and timber and return Passamaquoddy lands:

Your friends further state that they are in great want of a piece of woodland for the purpose of getting wood in the winter for the use of the elderly Indians, their women, and children, as they live on a point of land called Pleasant Point where they cannot procure wood, as all the woodland for the distance of thirty miles is owned by private individuals.

These are hardly the words of a tool of the colonial powers, as Kellogg understood Sockbason.  The fact that this Passamaquoddy man lived in a wood-frame house, then, was not what his white neighbors thought.  Settler colonists including William Kilby and Henry Thoreau were unnerved by literate Indians in wood houses: they found such people pitiful, tragic, assimilated.  But Sockbason was clearly trying to ensure that his own people had access to their own resources.  Kellogg tells a story of how the local priest tried to bar workmen from bringing a frame for a workshop ashore at Pleasant Point; Sockbason intervened, and the workshop was built.