So sorry to hear about your dad. Even with my dad it's a struggle to keep his weight but fortunately by the grace of God he can still eat anything though we limited his meat intake. I give my dad Prosure and ensure but prefer Prosure since less sugar content (when he was on feeding tube during radiation) boiled organic vegetables which we strain it throught the strainer with a teaspoon of coconut oil sometimes. Ghee sometimes etc when he can eat with rice. Coconut water almost everyday.
We are now fighting like hell and struggling but still we have hope ...
Now am researching cannabis raw juice/oil (cant find the oil at the moment) ...I think it looks very very promising.
Hope your Dad will bounce back soon. It's takes a short time to get unwell but long time to get better ...alway be positive(I know it's hard sometimes :( )
Good luck and God bless
Zoe