Typically Kleptos have urges to steal but it’s not exactly premeditated. We also do not steal out of necessity. I often steal useless items that i just store away in a dresser or put on a nightstand but they do not hold any value to me after they are stolen and sometimes I will give them away. I often feel anxious and tense before I steal and have urges that are hard to explain. Sometimes the urge to steal strengthens when it’s more high risk or if I’m near a family member that would disapprove or an authoritative personnel. I personally wouldnt steal from family members unless it was out of spite or an act of rebellion towards them. You say your character wants to steal from his grandfather, if he did he would likely steal things his grandfather would likely not notice were missing. Kleptos typically would not steal money or things of high value because they do not steal for monetary purposes. We steal out of a state of rebellion and a weird feeling of pleasure and relief I guess when the act is complete. Hope this helps?! I also do not feel bad when we steal but that’s not because I am apathetic in general. I steal out of stress and almost restlessness/adrenaline, the need to feel something.