Hi
I hope you have cured the problem now, but just incase is it a bungalow she lives in? If it is in the electricty cupboard for example where we store the telephone books, light bulbs etc. If the smell is still trapped, it must be in the items that are porus, ie phone book. Just sling it out and wait for a new one to be delivered. You could empty the cupboard and put a peeled sliced onion (on a plate-not plastic) inside for a few days. You could even paint the inside of the cupboard. Other porus items include anything made of wool/fabric. If repacement of said items are not on the cards, all you can do is what other people have sugessted.
Personally I have spayed clothes/curtains with Freebze and hung on the line on a windy day. Chairs/carpets/curtains spay again with Freebze and prop open all windows and doors.
I have found leather shoes/clothes are the worse. I just sponged them down with washing up liquid and dryed with a white towel then they went outside.
Just had a thought, has the wardrobe been put on an outside wall? Not a good idea. If yes, buy the small humidifers for boats/caravans which hold crystals and leave the wardrobe doors open when you are not in that room.
Hope this helps.