Bought this a while ago, in the end they were just too big for me and I decided I wasn't totally in love with the cut.
Size on the tag is XXL, I'd say it is closer to her 3XL size.
My measurements of the piece, taken flat:
Chest 60 in/152 cm
Length 21 in/54 cm. 
Alterations: I added elastic to the sleeves to make them more of a soft puff, and elastic to the shoulders to make them more narrow. This can easily be undone if desired. 
I do have cats. Please refrain from buying if you are allergic.