Small Bowel Obstruction - PEG Tube for Drainage

My dad has been battling stage IV colon cancer for four years now. He was not considered a candidate for surgery based on some other health issues so they recommended chemotherapy, which he received as needed for the first three years. The cancer went into remission once during this time, but unfortunately came back. 

About one year ago, the doctors stopped chemo after my dad was hospitalized for weeks with clostridium difficile colitis. He did not receive any additional treatment after recovering from the C diff and we found out earlier this year that the cancer was spreading. He had no pain associated with the cancer during this time.

Three weeks ago, he was hospitalized due to small bowel obstruction and they used a NG tube to drain the bile. The doctor’s feedback to us was that he would no longer be able to have bowel movements and their solution was to insert a PEG tube in his stomach for drainage (not feeding) so that he could go home and be able to drink and eat. They also recommended in home hospice care as a next step. 

After he was sent home, we did some additional research and asked the hospice nurse to try a stool softener. Since taking, my dad is having bowel movements almost every day. He was feeling pretty well until the last couple of days - he is losing weight drastically because he is not able to retain nutrients from the food he is eating because it is draining into the bag. He is not taking any pain meds because he says he is not in pain, just that he feels like he is starving to death and is getting weaker every day.

My questions are:

1. How can he retain nutrients with the PEG tube automatically draining anything he eats or drinks? The hospice nurse said an IV runs the risk of infection and does not recommend we proceed with that approach.

2. How is he continuing to have bowel movements if he is not retaining anything he eats or drinks? Also, why did the doctors not try a stool softener when he was in the hospital initially?

3. He has also been vomiting lately, typically after trying to eat something. We were under the impression that the PEG tube would help with nausea since everything he eats goes directly through it and not sitting in his stomach. Any idea as to why he is vomiting? 

Thank you for reading and any feedback or information would be much appreciated.