In need of some advice for my dad

So my dad was diagnosed with pancreatic cancer since October. He did the biopsy however an inconclusive result was given hence it had to be sent to the United States of America ti be tested. We are from the Caribbean. He has not started any treatment from the oncologist because he's awaiting result. However he has been taking seen a naturopathic doctor and has started treatment in the meantime.
He's talking digestive enzymes probiotic vitamins bowel mover etc. See some improvement in his sleeping and bowel movement.
Sometimes he feels nausea after drinking his lemon tea in the mornings or after eating a meal.
His eyes has gotten yellow. He mostly stays inside and lay down and sit up. Causing him to feel weak. He has issues finding a comfortable way of sleeping and has to be moving from one side to the other. He gets bloated sometimes and urinated something 2 to 3maz in the nights especially when he lays on his right side. Sometimes his feet get swollen.
Anyway of gaining weight??

Does anyone has similar situation and can guide me accordingly. Please I ask for guidance. I pray for all who are facing the situation