New baby and husband is gonna shut down soon

I have a 2 week old baby and soon my husband is gonna emotionally shut down for a week or 2. He always does every year on Sept 11. He lost both his parents on 9/11. He was 14 and his history class had it on the news. Both his parents worked there so he was trying to get in contact with them somehow. He also watched when the towers collapsed... He said he remembers everything around him slowing down and him screaming.... He was completely orphaned in one day.... He remembers waiting after school hoping they were okay and someone would pick him up... And someone did... A neighbor. Then cps was involved and he was placed into foster cares and had 3 family's. He said the first was okay. 2nd is where he suffered severe abuse and 3rd were more emotionally abusive and didn't want him there. He now also has a phobia of flying and this year will be extra hard because it will be 20 years.... Well.... Now every year old Sept 11 he shuts down completely for as long as 2 weeks. We have a newborn and honestly as bad as this sounds I can't afford for him to be shut down for a week or 2.... I know this happened every year but it's so hard with a baby. I just want some advice.

Edit: He's been in therapy for years. I won't lie. He's improved a lot, it's just that date that kills him. He used to shut down months at a time. Now it's just when September 11th us and a week or 2. I'm not denying his hard work just worried about having a baby with a shut down husband

Edit 2: I guess I could always ask my mom to help... I think I just panicked without thinking everything out... I know it's just a week or 2 and he has improved a lot.