Abbeygran I am so sorry - you must be feeling shock and grief and everything in-between.
I agree with Bluebelle - parental love is unconditional. It is not the same as 'like' and you can, when the time is right, express that you dislike what he did. So sad, but if the justice system takes its course and he does prison time, then the emphasis will change from sentence and punishment to rehabilitation over time and you could be key to helping him and his family with both current loss and later re-acclimatisation.
All that said, there is no 'right' or 'wrong', you just have to find your way for you through this and I hope you are offered the right help and support to find a pathway that helps you to process the complex feelings that must arise from this and also know how to support yourself and his family where approrpiate.
I could not imagine walking away if it were me and I get the impression you are deeply committed to the long haul, but bearing the cost of staying involved will only be apparent over time.
It may be that on top of all the other 'layers' that your AC is having to come to terms with, are guilt and shame for letting you down that might be very hidden / hard to express, or come out 'wrongly' at present. You could compound those feelings or relieve them to some extent by your responses and any support you feel able to give.
So hard for you. I am glad you can draw some support from posting here.