"I was just shattered for him. I sent him a text straight away but I just couldn't believe it," he said.
"Seeing the hard work he's gone through and for it to happen again is pretty frustrating for him, but I'm sure he'll be able to bounce back."
Scharenberg, 17, hopes to join his older brother at the top level via this year's NAB AFL Draft, having impressed last season for South Australia's under-18 team and even breaking into Glenelg's senior SANFL side.
"Seeing Matt go through his knee injuries shows that AFL life doesn't always go your way. It's not always smooth. There's a lot of challenges along the way and it takes a lot of hard work so I've seen that," he said.
"He's started his rehab back at the club now and he's happy with that, so I'm really keen for him to get back into it."