Terminally ill pt

One of the pts on my ward had recently been diagnosed with terminal cancer and the doctors had only given him a few weeks to live. He had just had palliative surgery and it was my job to get him up the day after his surgery. When i went in to see him and explain to him what we were going to do today the pt became quite aggitated and refused to get out of bed. When i went back the next day he refused again. As he was not refusing due to pain/ nausea/ dizziness etc my supervisor told me that he had to get out of bed today and that i should explain to him in some detail why it was important to get up after surgery. So i went back in and explained to him all the benfits of physio and ambulation post op. After i had explained this, the pt became even more aggitated and began swearing at me saying that i was pushing him too much and that i should leave him alone. On day 3 post op the pt finally agreed to come for a walk. He was able to ambulate independently and became aggitated when i initially tried to guard him. Whilst walking i questioned him on how he was feeling he again became quite aggressive and replied with 'why are you asking me that. Its a stupid question'
In this situation, where a pt has only been given a few weeks to live is there any point in pushing treatment on them like this? I was told by my supervisor to make sure that i treated him and i understand the benefits of post op physio but in hindsight i think it may be better to let the pt enjoy their life doing things that they want to do and not being pressured into things.