Perhaps the most important exercise that an obese client can begin doing is to become more active…. motivate them to just keep moving! Sometimes that in itself is a big accomplishment if they have been immobile for a good long time.
I would include cardio (for weight loss), strength training (increase muscle mass and metabolism) and stretching into their exercise program as I would with any other individual except it would have to be modified to accomodate their limited mobility and progression is key!
For a cardio example, I would have the client begin with short walks. If client is unable to walk even for short periods than I would sit the client down with a set of bike petals and have them pedal as fast as they can (hands or feet) for 30/60 secs intervals.
For strength training, incorporate functional exercises. Squats to a chair will allow them to rest when needed. Lifting dumbbells while seated will train muscle groups safely. Wall push ups, Smith machine push ups or my favorite TRX chest presses will target the chest and arms. Your client can also sit at the cable machine.
Although standing is preferable for optimal calorie expenditure your clent can progress from sitting to standing once improvement is evident.
Performing exercises on the floor (getting down and up) is challenging, so I would incorporate some standing or sitting ab exercises with a tube or med ball for core.
Using a small ball or yoga block placed between knees and holding in place with pressure will strengthen adductors.
Upper body stretches are more easily performed. You may need to assist your client with lower.
Be sensitive to your client. You are actually helping them reconnect with life! Remember to stress one step at a time!