Concerns about our child.

The fact is that our son took the news of our divorce in Mississippi very hard. In addition, there was a quarantine, my son didn't fully recover after it. He tries to hide his feelings from me, but I see that it is difficult for him to talk to me frankly. Sometimes I hear him crying at night, I go into the room, and he pretends to be asleep. I really want to help him, but I don't know how. The ex-husband left to live with his new girlfriend and isn't at all interested in his son. What can I do for him? Any advice please.