My Mum Has Formed A Fistula From Her Small Bowel

my mum has formed a fistula from her small bowel out through her wound following small bowel resection and now as soon as she eats or drinks it comes out the fistula. I feel there is no absorption going on any more. she is being fed TPN by central IV but is not receiving IV fluids and is not strong enough to be drinking enough. also she is receiving anti anxiety drugs orally. the only medication she is receiving sub cutaneous is Octeotrite (to stop secretions in the intestine) is this necessary