Although Bo Junyan was a cold person and had never been very enthusiastic toward his parents, he was someone who cared a lot about his family. He saw Ling Wei as his family. Naturally, he treated her like how he treated his family.
She was caught off guard and expressed her hope that he would lead a good life. When he got married, she would give him a great gift.
She also wanted to receive his blessings for her marriage.
Many a time, some people's indifference wasn't because they didn't care, but because they didn't like to express themselves.
This was also a common problem for geniuses.
It was just like how Bo Junyan got along with Mu Huan. If it weren't for Ling Wei's return, Mu Huan would not have gotten furious. Bo Junyan would have continued getting along with her most of the time. As Mu Huan said, he would at most reply with an occasional "Yes."
