Adoptee Strainer

My boyfriend, who was adopted as an infant, just heard from his birth mom for the first time ever. She contacted him out of the blue, sending a perfectly nice message, not expecting anything from him. Instead of responding to it, he's just sort of shutting down. Times are tough enough, and I don't think it's healthy to bottle up his feelings. However, whenever I point that out or ask him how he feels, he says he doesn't want to talk about it. How can I help motivate him to process his feelings?

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