Usage patterns
〈人〉を独りぼっちにするto leave someone all alone
She didn't want to leave her friend all alone.
独りぼっちになるto end up alone; to become lonely
After moving, he ended up all alone.
独りぼっちで〈動詞〉to do something all alone
He spent his birthday all alone.
独りぼっちの〈人〉a lonely, all-alone person
I saw a lonely old man in the park.