Facebook login problem, help me?

[Allie]

Okay, my boyfriend's friend is having trouble accessing facebook from his mobile device.
I don't know why in the world they would ask me to help, I know NOTHING about how the internet works, so I need expert advice please!

Okay, his friend told me that he tried logging into his facebook earlier today and it said something about saving the browser and he told it no, then it wouldn't let him back in. I've gone to his facebook and from my computer because it let me and it asked me to save browser in order to log in so I did, and then I deleted all the other devices it was logged into (except for the last 4.) I told him to try now, and he said that it said "secure connection failure"
What is wrong with it? What did I do wrong? and How in the world can I fix it for him?

He doesn't have a computer, just a cellphone so I have to do it all.

Please help me!