They sided with the highest bidders. Increase of pay and promises of big rewards in the shape of golden Kanthe
As Maharaja Sher Singh and Raja Dhian Singh was killed at the hands of Sindhanwala Sardars, Raja Hira Singh made a passionate appeal to the Khalsa Army, encouraging them to avenge the killing of Maharaja
The Sikh forces led by Maharani's brother Jawahar Singh and Sham Singh Attariwala overtook Hira Singh on the way and captured him along with his cousin Miyan Jawahar Singh, the son of Raja Gulab Singh.
From these events, its clear that the intrigues of Lahore court had also reached inside the Dogra clan. The Dogra brothers were powerful during the reign of Maharaja Ranjit Singh.
Maharajah Gulab Singh has taught us a thing that Chaos isn't a pit, Chaos is a ladder and it's all on us how we act that time.