Temporary absences exceeding 6 months UC claim

I have a client who currently has her children included in her UC claim and receives the CB. She also receives Housing costs for a 3 bedroom property.

The children have been in placed in the temporary care of the Grandmother and my client is giving money to her for the children. I understand that my client can still claim for the children and full Housing Costs as long as the absence is not expected to exceed 6 months. However she has now been informed that a court case that will impact on the custody of the children will not be heard until Feb and thus she will exceed this time limit.

Are there any exceptions where UC would allow the absence to exceed the 6 months? or will she simply need to notify them now of the expected delay as she knows it will exceed the time limit.

Thanks for any help.