If I have a 60 year old stiff as a board guy I choose exercises that will help develop deep core strength and flexibility.  Half roll backs can be done holding onto the legs or with a theraband though I might choose to teach some simple chest lifts instead.  I typically don't give teasers (even the prep) to this population unless they have enough strength and flexibility to do a simple half roll back or even a roll up.  When I do decide to progress them, a great way to modify is to hold a door between their legs in teaser prep as it helps to provide stabilization.  Hope this is helpful.