[nescioquid]

The psych literature on expertise draws in part from studying chess masters, and this expertise in chess mainly consists in recognizing a large number of critical positions. But this is founded in a fluency with tactics.

The parent is doing probably the most effective thing at their level by focusing on tactics, tactics, tactics. Learn the basic tactical motifs, practice finding them in puzzles, and practice employing them in games.

When you are starting with chess, don't study openings, just learn basic opening principles -- how to develop your pieces. Learning opening lines is the least productive thing you can do right now. The same positions can arise from multiple opening lines, so you are better off understanding principles and learning tactics (and how to calculate).