In the short term? Sure. If she finds it comforting, absolutely. She's not in her right mind. In the long term we'd make sure she understood what likely happened. As she'll be more rational.
Denial is part of the grieving process. Her son died a dozen or so hours ago. If she wants to believe he was shot by John Wilkes Booth, I'm not going to correct her tonight. I'm just gonna hug her and let her sob it out.
So much for the love you said you have for her.
Arguing with her on how her son died
the same day he died? Who would that serve? She's not in her right mind. She wouldn't accept the evidence. As she's working on pure emotion.
When she's had some time to process it, to work through some of the grief.....she'll likely come to the truth on her own. If she doesn't, we'll guide her there.
Again, expecting a grieving mother to act as if she's not grieving is unrealistic.