Advice on an ex friend

My ex best friend and I got into it back in December over something stupid and our friendship fell apart. It was both of our faults. We’ve been ignoring each other and just flat out refusing to acknowledge the others existence and that is just fine with me. Doesn’t bother me a bit. But I heard she lost one of her dogs, one that she was extremely attached to. I knew the dog too and he’s very sweet and is known for trying to get out. It’s been 3 days since they’ve seen him. Part of me wants to send her a message giving my condolences and that I’d keep an eye out. The other part wants to continue ignoring each other because reaching out would cause us to have to acknowledge the other. I’m torn on what to do.