"I think that in the past, her vision had been blurred," Michael, 22, tells PEOPLE in an exclusive statement of his sister, who voluntarily entered a rehab facility this week.
While admitting that his sister has made bad choices, Michael also says Lindsay's recovery has been hampered by her social circle.
"People she was surrounded by – enablers, leeches, whatever you'd like to call it – made things very difficult," he says. "It's quite strenuous to right your wrongs when the people around you help justify your actions. Therefore, cloudy judgment made it easy for her to neglect those trying to guide her."
Earlier this month, Lindsay, 24, Tweeted that she's "working hard to overcome" substance abuse problems, which are tough to overcome.
She Won't Get Better OvernightConcurring, her brother adds, "People with addictive tendencies do not get better overnight, so that cannot be expected. However, her commitment to her current recovery is a side effect of the realization of her past mishaps."
Lindsay, who failed a drug test earlier this month and spent 14 hours in jail before posting bail, is "well-aware that she's at a crossroad in life, and is fully committed to ensuring a healthier future," says her brother.
"She has made conscious efforts to improve her lifestyle behaviors and to treat this process with great care. In order to continue her healing process, she's willing to take whatever steps necessary," Michael adds. "We – her mother, brothers, and sister – have been there for Lindsay every step of the way – despite what trashy news reports – and will continue to give her our support and strength during these arduous times."
Last spring, Michael Lohan graduated from Ithaca College, where he studied business administration and played lacrosse. He remains close to sisters Lindsay and Ali, 16, and younger brother, Cody, 14.