The Pulp Fiction star's 16-year-old son died in January after suffering a seizure while on a family vacation in the Bahamas.
Five months later, Travolta is still devastated by the tragedy -- often breaking down into tears, according to Washington, who has been speaking to his co-star over the phone.
And Travolta has elected not to help promote the upcoming remake of the classic 1970s thriller while he is still in mourning.
Washington explains, "One moment he's OK and the next he's in tears... Needless to say, he's struggling. So more than talking to him, I listened to him, for about two or three hours.
"What can you say, really? Just be there as a friend, because he's such a sweet, sweet person. Our prayers are with he and his wife."
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