Simplify the following text for a Grade 9 native English-speaking person.
Original: He also made some ceramics and stained glass After Toulouse-Lautrec 's death , his mother , the Countess AdÃ le Toulouse-Lautrec , and his art-dealer Maurice Joyant made his art famous .
Simplified: After Toulouse-Lautrec 's death , his mother , the Comtesse AdÃ le Toulouse-Lautrec , and Maurice Joyant , his art dealer , promoted his art .