Can you possibly let go of that feeling of being "responsible" for their lives, Kiki? Perhaps every time you get that feeling, let that be your cue to do the opposite and bite your tongue? Remind yourself that ds and ddl are adults and can figure things out on their own. Please remember, too, that what worked for you might not work for them.
I notice that there was a whole week of your giving unsolicited advice to ds that culminated in a major discussion last night. That tells me that you and ds were contacting each other every day. Was that just this past week or is this the norm for you people? If it's the norm, some parents/gps would give their eye teeth for that! But it might be too much for your relationship with ds., especially if he's going to bring you his problems. He may be used to doing that from when he was a kid or a single young man. But he has a wife now, imo, he should be talking things over with her.
You may want to let ds know that it would help if you two cut back on communication. Then you wouldn't be tempted as often to give unasked-for advice. Also, you may want to ask him to give you fewer details about his problems or, even better, avoid telling you about them, at all. Let him know that when you hear he has a problem, you want to "fix it" - so perhaps better if you stick to more lightweight topics. Or if he begins to vent to you, listen for a minute or two, say something sympathetic like, "Aww" or whatever, and then change the subject to something more pleasant.