As someone who lost their father a few months ago, I'd say that the worst thing was that some people I considered close remained completely passive. No phone call, no message, no nothing. In the end, it turned out they were too afraid to call me and were afraid they would upset me, but it was completely misinterpreted by me as not caring at all and left a feeling of bitterness. So I'd say, call her, be brief and offer her help. You will notice if she feels like talking about it more or just leave it at that.