Some TMNT stuff was always meant for grownups.
Buscheyev is a character appearing in the City at War story arc of the Mirage continuity. He is neither a protagonist nor antagonist nor even a supporting character, but an innocent bystander who becomes collateral damage during the events of City at War. The story follows his life as a separate plot thread throughout the story arc.
In City at War, Part 1 of 13, Buscheyev lived in an apartment directly above Morph's Adult Novelties, a sex shop in one of New York City's red-light districts. In the midst of the ongoing open urban warfare between the warring Foot Clan factions in the city, a bomb was planted in the sex shop beneath Buscheyev's apartment. When it exploded, it completely destroyed both shop and apartment, but miraculously Buscheyev survived.
For the rest of City at War, Buscheyev's story is one of long hospital recovery and physical therapy, until finally regaining his mobility and a semblance of life in City at War, Part 13 of 13.