To help others and encourage them, you have to come from a place of love. It’s not all sunshine and lollipops, and it may require some firmness and possibly a hard line. Yet that will likely be well-received if they know you care.
In sports, on occasion, you will see some of the most excellent managers take a strict approach with their players. Those are the same ones who will place an arm around them, hug them, take them aside, and have a brief engaged discussion, especially when the individual may be less than their best.
It is a balance: when to push when to ease up, but it’s not one size fits all. Yet you will never be able to have the difficult discussions and command a positive response unless they know and convince them that you care. To be granted permission will require your effort upfront, genuine commitment, and ongoing demonstration far more than words, but supported through real intent and followed through in action.