Complex sentence: The union was deemed unsuitable by the Earl, who withdrew Ayliffe from the university in disgrace and disinherited him, which was by his father's will within his rights until Thomas turned 28.
Split into simpler sentences: The union was deemed unsuitable by the Earl, who withdrew Ayliffe from the university in disgrace and cut him out of his father's will. By the terms of the will this was within his rights until Thomas turned 28.