Me and my son had a heart to heart for the first time

My son moved in with me and my wife a few months ago shortly after we had our baby. His mom committed suicide and he found her with slit wrist. He was a mama's boy so I know that was extremely hard on him. He's in therapy and being here has been hard. Last night was the first time we had a heart to heart while playing basketball. We talked a lot about our relationship. I haven't been around a whole lot in his teen years. He never really seemed to want to bond so I thought he wanted to be left alone. I always called his mom to check up on him and tried to talk to him over the phone. He told me it wasn't that he didn't want to spend time with me, he just didn't know how without it being awkward. We eventually got on the topic of his mom. We talked about her for a while and he randomly started to cry. I rubbed his back and he said he didn't kiss her goodbye. When he left that day his friends were with him and his mom tried to kiss him goodbye but he was embarrassed in front of his friends so he didn't. And then when he gets home he found her like that. He thinks she killed herself because he didn't kiss her goodbye. I explained his moms battle with mental illness without trying to make her sound bad. My ex wife wasn't a bad person at all and she loved our son more than anything. I was honestly jealous of how close they will. I let him cry. He needed it. He kept saying he should have kissed her goodbye and didn't even say he loved her before she died. I told him she knows you loved her. We were outside for a long time. That was our first ever heart to heart. My wife was mad that I was outside for so long when the baby was crying, but at least we finally got to talk. I'm not his mom and I doubt he will ever love me as much as her but hopefully it's not too late to build a relationship.