My mother and I are pretty close and she loves her grandchildren so much

However we live 3 hours away from her. She tries her hardest to come over every other weekend to visit my 4 kids (ages 9, 7, 3, and 1)

However, my daughter takes it hard whenever she has to go back home. She always tells her not to leave and says she misses grandma for daaays after she’s left.

What can I do to help her through this? It stresses me out to see her sad over it