Giving feedback to spouse

Hello Nicholeen, how do I ask my husband to work on stop complaining and blaming others? He just asked me to give him feedback on one thing that he could work on his character during the summer. That was an answered prayer as I've praying and working on not criticizing him and not complaining about his flaws. Now that he has asked, I don't want to mess it up. He's SUPER smart and ahead of most at his company, and often complains about how the people he has to deal with at his job don't listen to him, and don't keep up with what he says. Then everything blows up, and he has to fix it. He talks about it almost everyday as it surprises him or it's something new, but it's not. He also makes excuses for things that he doesn't do or not accomplish. such as, "oh I wanted to hang that frame you asked me about, but I don't have nails", "oh he got the job at that awesome company because he went to an ivy league school and I didn't", "oh she probably got that business from her parents, she's probably a trust fund baby", "his parents supported him and guided him when he was young, that's why he's achieved so much, but my parents didn't care or went to see me compete, or supported me in any way", "Oh I have ADHD, so I can totally listen to you while scrolling through my phone", then proceeds to ask me to repeat what I was saying to him, etc. He does recognize that he tends to be negative, but it comes out very frequently that makes him sounds like a downer, whiny, and as someone who doesn't want to take responsibility for anything.
I must add that he has a really good job and has always been responsible in providing and caring for us. He does come from a permissive family and his mom (single mom for a while) shows the same traits mentioned above.
I come from conservative and strict parents, who I don't remember ever complaining about tough times.