This is the house rule I use for the rare case that a player character wants to use another player character for a patron or pact.
Sorcery and Player Characters :
A player character may act as a patron or initiate a pact with another player. The player taking the talents of Patron, Pact or any talent that has the root of Patron (such as Sorcerer or Necromancer) may only learn skills, petty enchantments and spells that the player providing the Patron or Pact knows.
The demand of 5 CD gold/vigor/resolve must be paid each upkeep as normal, though the Player Character receiving the demand does not gain any benefit. Nor do demands cancel each other out, such as in the case of two players forming a pact with each other.
The only way to remove the demand is to forsake the patron or pact, or for the Player Character that “receives” the demand to perish. In the rare case that a character dies and is raised within the adventure, the patron or pact is not forsaken, and the demands still stand for the next upkeep. Otherwise, the pact or patronage is forsaken as described in the core rule book, and cannot be reacquired from that character, even if they are raised from the dead.
In special circumstances, the GM may allow a dead character to continue as a patron in the form of a spirit or ghost that has limited interaction with the living world.
Once a character forsakes a patron or pact, that character cannot enter into another patron or pact relationship with the forsaken character. A new tutor must be found, as described in the core rules.
In the Monolith sourcebook, there is a spell book item that lets players learn spells as though the book were a patron. The book requires no demand; but must be studied with a D4 sorcery test. If successful, the player starts the next adventure with one trauma and may spend 500 points to gain a new spell. For book keeping purposes, this is represented by the trait Spell Book Learning .
New Trait: Spell Book Learning : Sorcery, one rank, may be taken multiple times, Requires Sorcerer trait, costs 500 experience (Not Reducible)
The character taking this trait must have succeeded at a dire (D4) difficulty Sorcery test during carousing to study a spell book to learn a spell. The character pays the permanent resolve cost for a spell, and learns that spell. The GM should adjudicate which spells can be learned from the book ahead of time, and may choose to select (randomly or not) which spell the character learns. The character must know the basics of Sorcery through the Sorcerer trait to benefit from the spell book, and the spell book learned spells can be effected by the loss or destruction of the book similar to the loss of a patron.