Female person hearing voices from inside

My grandma recently expired due to covid 4 months ago. My mother could not see my grandma for final visit on her deathbed. She seriously got depressed at that time. But everything was fine after 2-3 weeks. My mother started behaving weirdly for 2 days. My mother watches spiritual videos for long time and good devotee to god. But, for 2 days she is saying she has hearing voices inside and voices are coming from God. She is telling that she is god. She is constatnly saying mantras in loop. Asking us to take photo of God , photo of her. We have never seen this kind of behaviours in her. We are pretty much worried. She always keeps telling us that she is perfectly alright. She is resisting to go to hospital for a mental health check. Please help us.