It is a popular idiom that describes the leisure life of elderly people.
含: keep something in mouth
饴: syrup / candy / suger
弄: play with
So this idiom means to play with grandchildren with candy in mouth.
You can also check its Chinese explanations at 含饴弄孙:
hán yí nòng sūn
The links in my answer point to an online Chinese English dictionary, which has usage examples that extracted from China Central Television (CCTV) news. You can see the most fresh examples of the words you are looking for.