Jacob Grimm is Sabrina and Daphne's uncle.
Jacob was (inderectly) responsible for Basil Grimm's (his father's) death. At the time Henry was in love with Goldielocks.
Jake thought it was good to let Goldielocks free from the barrier, ( so did Henry.) Uncle Jake snuck into Baba Yaga's house, looked in a spellbook and let the magical barrier down. The spell also let down the barrier surrounding the insane asylum.
The spell let Little Red and the Jabberwocky free, who in turn killed Basil Grimm.
Sabrina, Daphne and Puck meet their uncle (and friend) when they return to the insane asylum. They encounter him yet again at the opening for the new school, Charming Elementary. Jake has many adventures with the family, such as going to the Blue Plate Special- The Problem Child.
Sabrina sees her uncle getting shot by in arrow, nothing much-Magic and Other Misdomeanors. Well, something does happen in book seven, he does get shot with an arrow. He gets help from Nurse Sprat. But when he should be resting, he goes to help Brair Rose( who was getting stalked by the Scarlet Hand)