Tracy Morgan Is 'Having a Tough Time' Recovering from Crash Injuries, Says Lawyer

08/28/2014 AT 03:40 PM EDT

Tracy Morgan hasn't lost his trademark smile, but his road to recovery remains a long and arduous process.

"He's really having a tough time," his New York lawyer Benedict P. Morelli tells PEOPLE.

Since a six-vehicle crash in June – which left Morgan in critical condition and ended the life of his friend, comedian James "Jimmy Mack" McNair, 62 – the 30 Rock star , 45, has been "struggling," Morelli adds.

Though Morgan has been spotted using a walker, he relies on a wheelchair and it may be months before he can fully walk again.

Having suffered traumatic brain injuries, a broken leg and several fractures to his face, Morgan continues to undergo at-home therapy following his release from a rehabilitation facility in mid-July.

"He's making incremental progress," says Morelli. "But they'll have to wait another month before they assess him cognitively."

• Reporting by MICHELLE TAN

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