At goal weight, now what?

My mom has recently cut out a lot of sugar due to threatening diabetes and has started working out. She has lost a few pounds and doesn't want to lose more. (She's at a healthy weight for her height). She has stopped working out to keep from losing weight. I told her that stopping her workouts is not wise that she should up her calories. That if she's eating enough and working out she won't waste away that her body will naturally stop losing when she reaches optimal weight for her. I also told her to maybe switch to strength training instead of cardio to build muscle mass. Did I giver her the right advice? Is there anything else I can tell her? She is in her early 60's and very healthy.