en_tn_lite_do_not_use/luk/02/51.md

he went back home with them

"Jesus went back home with Mary and Joseph"

was obedient to them

"obeyed them" or "was always obeying them"

treasured all these things in her heart

Here "heart" is a metonym for a person's mind or inner being. Alternate translation: "carefully remembered all these things" (See: rc://en/ta/man/jit/figs-metonymy)