When Magwitch first appears, Pip is horrified. His reaction is partly due to the ungrateful and selfish person he has become while transforming himself into a gentleman. However, it is also partly his disappointment at finding out that Miss Havisham is not the benefactor, and he is not meant for Estella.
All this time I had never been able to consider my own situation, nor could I do so yet. I had not the power to attend to it. I was greatly dejected and distressed, but in an incoherent wholesale sort of way. (ch 60)
Once Pip gets over the shock and gets to know Magwitch, and learns the full story, his attitude changes completely. By the end, Pip looks at Magwitch like a second father. He goes all the way back when tricked by Orlick’s letter to make sure that Magwitch is not in danger. He also goes along on the boat trip to sneak him out of the country, even though he was injured trying to pull Miss Havisham from the fire.
“Thank'ee, dear boy, thank'ee. God bless you! You've never deserted me, dear boy.”
I pressed his hand in silence, for I could not forget that I had once meant to desert him. (ch 56)
It is clear then that Pip has changed. He now knows what love and family really mean.