What is the name of the movie …where a boy shrinks to save his grandfather’s life and enters his grandfather’s body?
He fought the illness and finally his grandfather got better
Stonebroke Answered question Jul 11, 2022
Hmm, people shrinking and curing people, but no grandfathers:
Fantastic Voyage
https://www.imdb.com/title/tt0060397/
Innerspace
https://www.imdb.com/title/tt0093260/?ref_=fn_al_tt_1
Stonebroke Answered question Jul 11, 2022