Pluto in the 4th House represents someone who was born in a family where feeling safe was somewhat impaired. Sometimes, the conditions of childhood were quite dangerous, or abusive, but sometimes, it's much more subtle than that. Something in the family and childhood could have happened which represented a "shock", something that disrupted the feeling of being safe and loved in the home. Often, we find people who are born in families where the dynamic was one based on control and power, and it's possible they had to assume the position of scapegoat or black sheep.
It isn't always this dramatic, although it can be, but overall the main energy of this position of Pluto is that what should have felt as a safe and comforting environment was more so a source of anxiety and intense feelings. IF Pluto is very well aspected, then we can sometimes see someone who was born in a family/environment that allowed them to feel particularly powerful, empowered, and able to rely on them for a source of power. But more often than not, this isn't the case.
With this position of Pluto, we find people who compulsively seek a feeling of nurturance, love and safety - but often, the more they seek it in others, the more they find themselves feeling unsafe and unprotected. Pluto represents our personal power as well, and as much as the person is not keen on doing so, the power of this position of Pluto is to learn how to develop emotional resilience, counting on yourself, being your own safe place, being your own nurturer.
The more someone with this position learn how to become their own powerhouse, the more love they have to give, and the more space they have to receive a love which feels nurturing, safe and kind. As well, the more the person focuses on developing emotional autonomy, the more close relationships and relationships with family can become a source of fulfillment and power.
It is likely that the childhood conditions and type of nurturance pushed the person to believe that emotional manipulation was the way to obtain love; as I said, we often find family dynamics based on power struggle and control. It doesn't have to be malicious, more so - a learned way of dealing with emotions. For example, often with this aspect we find a household where withholding love, passive aggression, subtle remarks and stings, stonewalling, manipulative displays of emotion, could have been the main way of dealing with each other. There can also be codependency, enmeshment, and an overall toxic use of emotions. Looking into what a healthy relationship looks like can be very useful once adult.
Personal readings available
"Pluto an evolutionary journey of the soul": By Jeff Green
"The book of Pluto": Steven Forrest