He is obsessed with having LD's full attention to him and only him. Dude! he doesn't even let LD's own mother and father have any sort of say when it comes to LD, let alone Radha! Up until now, all the other people in the family have been under his control..but when Radha made an entry in LD's life, he saw her as a competitor.
What the hell is he planning to do in the precap? He's incorporating goons to get rid of Radha?
Sometimes, people who boast the most about morals and religion are the ones who are the perfect examples of being the most immoral and inhuman of all! Dadaji is definitely one of them. He plans to use wrong means to justify what he thinks is right. His truth needs to be out soon enough and would like to see his entire image/respect falling in the eyes of his "beloved" grandson. Then, LD needs to move to Mumbai with Radha and carry on their lives away from him and his so called "sanskaars."