Liam Neeson, Sons Sit Courtside at Knicks Game
04/16/2009 AT 04:30 PM EDT
Liam and sons Micheal, 13, and Daniel, 12, took in a New York Knicks game at Madison Square Garden with pal Aidan Quinn on Wednesday. The four sat courtside, where Neeson smiled and applauded as the Knicks beat the New Jersey Nets 102-73.
The family was also seen taking an Easter visit in Saint-Tropez – where they vacationed before with Richardson.
"He's a strong man, but this is difficult," a family friend tells PEOPLE. "He now has two sons he is solely responsible for and in charge of. He's a solid guy. His feet are planted on the ground. But this would be difficult for anyone."
Neeson also has signed on for his first movie role since Richardson's death. The actor, 56, will play Zeus, the king of the gods, in Clash of the Titans.
With reporting by KC BAKER