Complex sentence: Currie nevertheless ordered a detachment from Chattar Singh's army under his second in command, Jundial Singh to reinforce Sher Singh, which allowed Jundial Singh and other officers to influence Sher Singh and spread disaffection among his regiments.
Split into simpler sentences: Currie nevertheless ordered a detachment from Chattar Singh's army under his second in command, Jundial Singh, to reinforce Sher Singh. This allowed Jundial Singh and other officers to influence Sher Singh and spread disaffection among his regiments.