@karimullaN

In a customised way its possible. When the attachments are uploaded in the child case, it'll be present in the common repository linked to the case. There you can create a logic to link it to the parent case too. The parent case details will be available in the cover page.

@karimullaN please use pxLinkattachmenttocase activity to copy your attachment from child to parent... You just need to pass parameters, pega will take care of copying attachments. 

Alternatively you can pass your child case pzinskeys to pycaserelatedattachment section (ootb section to display attachments). You need to have a pagelist with child case pzinskeys and source table/repeating dynamic layout with this pagelist keeping pycaserelatedattachment embedded. So for each rows in the pagelist (having pxcoverinskeys), it will fetch respective attachments.