I feel like sometimes, people tend to forget that Cherri is an addict herself
Cherri was widely criticised for pushing Angel to relapse and of course, that's horrible, and I'm not saying it was the right thing to do, but we shouldn't forget that she's very much an addict herself and still deep down the rabbit hole.
It makes sense that she doesn't have the best advices, because she has no desire to get better herself. As a friend, she should have supported him right away, but as an addict ? It's more complicated.
One other important point is that Cherri is aware of Angel's personal Hell, she has seen him self-destructing and being abused by Val for decades. Drugs, partying, turf wars : all these things are their escape. Knowing he just had a hard shoot, I think Cherri wanted to help Angel in the only way she knew how.
I honestly think she didn't really realize he was being serious about redemption either. After all, she wants him to be happy and when he's at this lowest, she holds him and hear him out. However, being an addict herself, she can comfort him, but she prolly thinks she can't save him completely.