Advice? UPDATE

Okay guys. So I left my husband a little under 7 months ago when my son was 2 weeks old. He nor ANYONE on his side of the family has tried to see my son. we are in the middle of a nasty divorce and custody battle. His family thinks he’s done no wrong, when he’s physically mentally and emotionally abused me, and they have witnessed it. Anyway, today out of the blue, his mom texts me and asks for my sons social security number for her beneficiary paperwork for work. Does that even make sense? I have this fear that she needs it for something else and won’t tell me. My mother in law and her son are very shady deceiving people. Why would she want to put him down when she never reaches out or tries to see him??? I’m so stressed. Am I being paranoid?

**to be clear I’m NOT going to give her the SSN, I was just curious if anyone else found that strange or if anyone knows any other reason why she would need it**