Losing weight is all about numbers. If I can increase the number of calories I can burn in a day, I can lose more.
Once I figured out my maintenance calories then subtracted 500 calories to lose and include regular movements, I lost weight, like clockwork!
As you get stronger, you may not lose weight at the same level of activity and calories as before. Change things up, use different muscles or increase your time. If you feel stuck in your weight loss, check out this article, "Why am I not Losing Weight in a Calorie Deficit?
If you are older than 65 this resource from the CDC contains detailed information about exercising.
If you are helping someone who is older and struggling to feel motivated to exercise this article for caregivers might be helpful.
For someone over 70 this article shows that 'not' exercising but purposeful movements are better.