You know, the absolute best bet for yuor parents is not cardio VHS worrkouts at all. Encourage them both to just get out and walk. The benefits of this are enormous. They would be together keeping eachother company. Your dad already likes to walk, so he would be encouraging his wife to walk with him and keep fit. The fresh air and scenery is way better for them mentally and emotionaally than staying on treadmills at home. They could also form a walking group with others of their age in town. There are groups like this in Ann Arbor where I live. Seniors groups who meet at different parks and woods around the area and walk there together for a few hours, then in Summer/Spring they could all settle down for a picnic and make their health requirements into a social gathering. Too many retirees get socially isolated after work ends, so this would be a good way to snure that they and other seniors in their area are not falling by the wayside. Social gatherings and contacts are an essential part of mental health, which in turn, is an essential part of general overall well-being.
My parents are both in their 70's and there's no way they could complete cathe videos. It's way too mucch forthis age group generally speaking, even though my Dad was a footballer and runner all his life and a gym rat in his 50's and 60's. But they go on walking vacations with their ffriends and they love the combo of health and social gathering that this provides.
If they want to lift weights also, which is a great idea, they only need a program which will stick to the bascs for them, i.e. 2 exercises per body part, the most compound moves. At this age, they are not interested in sculpting terriffic abs or triceps, and neither do they need it.
If there is a local gym with sports trainers available in them, this is again the best way for them to go. They will need professional guidance, at least at first, to make sure they avoid injury which is easier to accrue at their age than at ours. And again, it gets them out of the house and then they could hit the tea rooms afterwards and have more fun!!
Clare