Since your dietitian has access to your medical chart and I don’t, I would recommend you follow her instructions for a protein powder. You probably need the extra protein because the proteins in your blood are low or it is helping to cure pressure sores.
Pulmo Care is lower in carb which won’t increase your oxygen needs. Are you on a respirator? Ask the Dietitian why you are on the protein powder and Pulmo Care.
A 1200 calorie diet plus 355 calorie supplement? Calories in protein supplement should prevent additional weight gain which would not be healthy. Additional weight would also increase your transfer weight (someone moving you from wheelchair to bed) and pressure on boney points i.e. heels, hips, tailbone, shoulder, and back of the head.
You don’t mention whether or not you receive physical therapy. Passive range of motion (someone moving your arms, legs, torso) can help maintain muscles and prevent contractures (muscle shortening due to disuse). As a resident in a health care facility, you should be receiving some maintenance physical therapy. If you aren’t in some PT, ask your nursing staff what they could schedule for you on a daily basis.