I completely understand where you're coming from, DM was a bit like this.
But standing back, To give her her due, it's a two hour trip to do childcare for you, if I uunderstand you correctly and although I'm sure she wants to do it, it's tiring, not adult conversation, and two hours back. It may well feel a long way.
She's lonely, still grieving, probably wondering if she gives up the childcare she'll lose you, really needing to be needed, esp if she was the caregiver for your father. I'm not saying she's right in how she expresses this, far from it, but I do think the length of time it takes to get over bereavemenr is often misunderstood when it comes to the career.
Like another pp I wonder if there are things she can get involved in, perhaps with you to begin with? Could you join a Saturday club with her, going alternate Saturdays, or something?
If you think she's depressed, which she well might be, : doctor -pills or counselling, she may well need to talk. And talk. And talk.
Then, cruse, the organisation for widows/widowers, being able to explore your feelings, talking there.
And getting involved with people. She's prob v v lonely, not your fault. If you can help her find a day time voluntary organisation that's crying out for help, that's a good one. Doing something for other people gives meaning to life. Given your DF died of cancer is there a local hospice, or Macmillan? Evenings are tricky and lonely: a choir? Training to be a St John's ambulance person - they are always needed..
We found that if we suggested something it was vetoed. If we told DM that one if her friends was doing x, or that y was mentioned in the newspaper, or even better got one of her friends to mention it, it had a much greater chance of success.
You're not wrong, her demands are too heavy. And she's jealous. But she will need help finding and doing stuff.