Chemo tomorrow I am worried !! Help !

Dad is having chemo tomorrow gemza/carbo. As I have posted before he is 91 and has advance lung non-small cell metastisized to liver and lymph nodes. He has become so weak in the last 2 weeks it is unbelievable. The dr. says it is cancer fatigue but it is knocking him down fast. He can barely walk at all and sleeps almost all the time. I am very worried abou this chemo. The dr. is giving him the full dose (according to his nurse) of this combo and I don't think his body can take it but my dad wants it and thinks it will help him. I don't believe that it will and that he is too far advanced. Will they see this and maybe not give him the chemo? Will things show up in his bloodwork to stop them? My mother had lung cancer 18 years ago and it was in her whole body and they gave her chemo and it killed her. If anyone can give me any advice to take with me tomorrow it would be very helpful. I don't know what to expect and don't want to lose him to the chemo like I lost my mother. Thanks to all !