I'm losing my brother to religion

For context he's 21M . My brother was/is a stellar, went to among the best high schools, that guy was the golden child. He has been prayerful since his childhood , which we have been proud of .

Last 3 years he's been battling skin illness which he resorted to fasting and praying,we used to warn him coz he was too young to fast for days .He didn't listen.As he was almost joining campus ,he couldn't imagine enrolling withskin issue,it got worse that he was diagnosed with major depression,He deferred,for 2 years.

Hio skin issue could be dealt with,fast forward to now,he joined this year and he didn't do his CAT's . We were shocked.He isolates himself ,he leaves us at the living room to go pray at 9:00pm and i was awake at 5:30am and he's still praying.

We have tried talking to him,for me i'm not always easy when it comes to it,i'm very logical. My dad has tried ,but he fears being tough on him so he can't commit suicide(he once found him trying to hang himself) and he kept threatening to kill himself i gave him a rope,he didn't.

Guys ,i need ideas on how to deal with him or i let life teach him ,coz clearly this is not it.