Alex let Pearl do whatever he wanted. Pearl didn't really have anything to do in a confined room, so he cultivated all day long.
Whisker, however, was in his element. Alex gave him a cauldron and some ingredients and had him make pills.
He watched over his techniques and skills in making pills and was pleasantly happy when he saw the Whisker was very good now at making pills. He was still only making pills without around 40% harmony, but that was only because Alex was giving him the bad recipes, instead of the fixed ones.
He wanted Whisker to start from the bottom like everyone else would, and struggle the same way a normal alchemist would, something he never got to experience.
He didn't know if helping someone this early on with an easy way out with ingredients and recipes was even a good idea or not.
If it turned out that it only made Whisker more demotivated towards Alchemy, then he would certainly give better ingredients and recipes.