First, the relationship between Jia Mu and Lin Daiyu is profound.
There is a special introduction in the fifth story of A Dream of Red Mansions that the relationship between Jia Mu and Lin Daiyu is very close, and Lin Daiyu is the granddaughter of Jia Mu. You know, although Jia Jia has a lot of children and grandchildren, Lin Daiyu is the only real granddaughter, so Lin Daiyu's position in Jia Jia's heart is of course very important, which we can feel in the dialogue between the two, so Jia Jia loves Lin Daiyu in formation.
Second, Jia's deep love for her daughter was transferred to Lin Daiyu.
From the first eight chapters of A Dream of Red Mansions, we can see many language expressions of Jia Mu, so as to understand Jia Mu's inner world. Among them, Jia Mu especially talked about Lin Daiyu's mother, expressed her deep attachment to her daughter, and also revealed Jia Mu's grief over her daughter's untimely death. She also specifically told Wang Xifeng to treat Lin Daiyu well, which shows how much the old woman lamented her granddaughter.
Third, Jia supports Baodai's love.
When everyone was watching A Dream of Red Mansions, Jia Mu said Lin Daiyu and Jia Baoyu more than once, apparently to publicize their love and marriage. Jia doesn't care about his granddaughter. How could he make such a decision? It was only after the death of Jia Mu that this matter was changed!