Texting ex bf's mom

My LDR ex bf and I broke up in April. His mom and I are in the same country and used to text back and forth sometimes. The last time we texted was 2 days before we broke up and I haven't seen her since March.

On Monday she texted me to say hello and that she hadn't heard from me in a while and wanted to know if everything was okay. I didn't message her anymore because it would have been awkward for me to do that since I'm no longer with her son. But I got the impression that she didn't know we broke up and we chatted like normal. I didn't mention anything about the break up to her.

My question is should I keep messaging her and checking in? I don't want to not message her and she keeps messaging me especially if she doesn't know we broke up. I don't mind still talking to her but if she doesn't know or if she does know I don't want it to be awkward. I think my ex should be the one to tell her. What do you guys think?