hi,thought id give you my advice on your difficult dilemma whilst i wait for the last of my 3 cats to come back indoors,she'll want to stare at the garden wall for 5 more mins anyway....now then,if it were me in your shoes i'd do whatever it takes to let the two dogs remain together.whether that means you have them both live with you or,your mum has them both.either way they really shouldnt be parted.they'll have a special bond with each other now.they look so lovely together!so cute.hope this helps you in some way.take care.jackie.x