Jamie Leigh Twidale, 24, was found slumped over the bathtub the next day after four-year-old Harley and three-year-old Skyelar failed to turn up for school .
The youngsters thought their mother was asleep and climbed naked into her bed at their home in Hartlepool, Co Durham.
The children’s grandmother Elizabeth Twidale was called by the school after they couldn’t get an answer from Jamie Leigh and she went round to the house to check on them.
When she got to the home on October 31, she found her daughter slumped over the bath and the children undressed in their mother’s room.
Elizabeth said: “The school had tried to ring Jamie, but couldn’t get an answer. They knew about her epilepsy and called me.
“When I got to the house I could see the kids’ uniforms ready and it was really quiet.
“I was shouting for Jamie, but couldn’t get an answer.
“I went up the stairs and could see Harley wasn’t in his room, and when I turned I could see into the bathroom and saw Jamie slumped over the bath.”
Elizabeth said the children then came out of the bedroom of the house but thought their mummy had just been sleeping.
She added: “It looks like she had bathed them on the Sunday night and was emptying the water out when she has had a seizure over the bath, which is why the children didn’t have any clothes on.”
Elizabeth, who is also mum to Aaron, 18, said Harley and Skyelar hadn’t realised that anything was wrong and didn’t understand their mum isn’t coming back.
She said: “They just keep saying that she is asleep.
“She was a fantastic mam, she lived for the kids, they were everything to her.
“We used to spend almost every day together, she always had a smile on her face. It hasn’t sunk in, I just keep thinking she will come through the door.”
Elizabeth is now preparing to care for Skyelar and Harley and said she has received a lot of support from family and friends.
Her family have set up a fundraising page to help raise cash to support Skyelar and Harley in the future.