To go along with the weight gain powder idea, you can doctor them up to make them more tolerable. Like meal replacement shakes and protein powders, most taste like garbage straight. However, I found by adding fresh or frozen berries along with either cow`s milk or almond milk instead of water, many are actually tolerable. It also boosts the calorie count as well.
Also, muscle mass is more dense than fat and will produce bigger gains when trying to put on weight. Are you to a point where short walks or a gentle spin on an exercise bike is possible? Maybe some light activity to prevent the loss of additional muscle and maybe restore some that was lost might work? If nothing else, it might make you more hungry so you can pound back more of that delicious looking food you posted.