Casey Affleck has praised his brother Ben Affleck for his ''very brave'' decision to return to rehab.

The 'Old Man & The Gun' actor says his older sibling - who checked into a facility in Malibu three weeks ago as part of his battle against alcohol addiction - is ''getting better'' and he is ''looking forward'' to seeing him back on the right path.

He told E! News: ''He's an alcoholic and he's in rehab. He's recovering and I think it's very brave of him to take care of what he needs to take care of.

''He's handling his business and getting better. I look forward to him being out and back on his feet.''

And the 43-year-old actor revealed the 'Justice League' star is ''doing great'' with his treatment.

He told 'Entertainment Tonight': ''He's doing great. He's in rehab and he's recovering and seems to be doing well.''

Ben entered rehab after his ex-wife Jennifer Garner - with whom he has children Violet, 12, Seraphina, nine, and Samuel, six - staged an intervention, and she's said to be thrilled with his decision to give treatment a third try.

A source previously revealed: ''He told Jen and was not resistant. He asked her to take him and she wanted to be there for him.

''She wants him to be clean and healthy and will help him get there if he's committed. She is glad he is in a safe place and getting the help he needs.''

Though he's committed to his recovery, the 46-year-old actor has been making frequent trips home from the clinic so he can use his own gym.

A source said recently: ''Ben is working out at his house. He goes home to his gym to work out with his trainers.

''Since last week, he's been driven from the clinic every day from rehab to the house to work out. For a few hours a day. He's always accompanied by his coach and therapist.''