It's rude not to want your grandparent around you.
Jonah's grandfather calls him to tell him that he's been evicted from his house and needs his help.
Jonah wants to secure a place to live for his grandfather.
Jonah tells his grandfather that he can live with him and that he has nothing to worry about.
Jonah tells his grandfather that he will find an apartment and that he'll help his grandfather pay for it.
Jonah's grandfather is delighted and relieved to hear he can live with his grandson for free.
Jonah's grandfather is sad to hear that Jonah would rather pay for him to live elsewhere than invite him into his home.