What is the ruling on mixing between genders on social media for the purpose of recalling memories, and how can they be advised to stay away from that?

The presence of boys and girls in one group on social media platforms is not the forbidden physical intermingling (ikhtilat). However, one must adhere to the Shariah guidelines and avoid everything that leads to temptation. If these guidelines are observed, then there is no harm; otherwise, it is not permissible.