When I got home post-transplant I still had horrible pain from mucositis and issues with taste. My tongue felt like there was a tablespoon of salt on top. Most everything tasted disgusting. I lost a lot of weight because I struggled to find anything that wasn't nasty. I forced myself to eat something everyday.
Spicy foods were easiest. Coffee was gag-inducing. That lasted for the first 3 weeks at home. Once those problems resolved my appetite improved and my nutrition issues ceased. I wish the same for your dad.
Diagnosed with MDS-EB2 December 2017. Stem cell transplant completed August 2018.