Help with a New Program for My Dad

My dad’s 55 years old and he doesn’t have any experience in weight lifting/training at all and the most exercise he’s been getting the past few months is when he’s at work moving stuff around. So basically he hasn’t done any proper exercise for almost 20 years so I want him to get into it to better his overall health. He’s got scoloiosis on his lower back and a minor problem with his elbow joints (will get more details on it when I can).

What exercises would be appropriate for him? Should I make him do a lot of body weight exercises like push ups against the wall and something like quarter squats for starters? Maybe have him exercise 2 or 3 times a week? I’ve only got a barbell and dumbells and a treadmill for him to work with at the moment.