As other's mention below, weight lifting really is its own special thing. But definitely, just getting moving, consistently, is an excellent place to start.

A lot of people in wealthier countries work until retirement age and then park their asses on the sofa to spend the remaining years watching (awful) TV and getting fat and unhealthy. That's not living, and it's a guaranteed path to sadness (and frustration for the children who have to help the parent). Not to say that children shouldn't give back and help the parents, but it's still super important for all parties involved to be making effort.