The "Stronger" hitmaker has been fighting to end her dad's role as sole conservator of her estate for months. The conservatorship was put in place in 2008 after Britney's much-publicised breakdown.
The situation led to Britney's devoted followers launching a #FreeBritney movement, but Lance told Entertainment Tonight that he's spoken to the singer's sister Jamie Lynn Spears - and consequently feels much better about how his pal is doing.
"I have talked to Jamie Lynn recently, which is why I feel so much better about this situation," he said. "They aren't as worried as we are."
Insisting that the public "have no idea what's really going on," Lance urged Britney's fans to "trust that the loved ones around her are doing the right thing."
"The one thing that I do know is, I know Jamie Lynn - if Jamie is OK with everything going on, I feel like she really has her sister's back during all this," he said. "So I trust her to give us the real information."
Britney Spears' conservatorship was recently extended with her dad James back as a sole guardian. Sister Jamie also filed legal request to gain more control over the hitmaker's assets. She asked judge to have her older sister's assets transferred into new accounts with her as a custodian.
Jamie recently hit back at the critics, insisting they had "no right to assume anything about [her] sister." Brother Bryan also defended the conservatorship, "It has been a great thing for our family, to this point, and (we) keep hoping for the best."