Infirmary Healer // Stream of Life

Creating a copy of a creature's prepare spell in exile ignores copy exceptions applied to that creature that would affect the copiable values of that spell. For example, say a player casts Croaking Counterpart (a sorcery that says "Create a token that's a copy of target non-Frog creature, except it's a 1/1 green Frog.") targeting Goblin Glasswright. The token copy of Goblin Glasswright will enter prepared as a 1/1 green Frog creature, but the copy of Craft with Pride in exile will still be a red sorcery. The copy of Craft with Pride won't be green, a creature, or a Frog, and it won't have power or toughness.

A creature without a prepare spell can't become prepared.

If a prepared creature stops being a creature, it will still be prepared, and the copy of its prepare spell will remain in exile. That permanent's controller will still be able to cast it. The same is true if a prepared creature becomes a copy of something else, even if it's then a permanent without a prepare spell.