These days middle aged people still living with parents is becoming more normal, so I might be willing to overlook it if I were dating again, but it would be weighed against other factors. Their relationship with parents is definitely a biggie and it sounds like your ex and his mother are enmeshed to a degree. I mean, it’s ok to be proud of your child, but nobody with things going for them already - tangible things they worked for/on themselves - has to be promoted at every turn, like they’re a pyramid of canned goods in the supermarket.
You should be able to see at least some of those good qualities without much input from a cheerleader squad, or find out about them in a more ‘organic’ way as you get to know the person better.
As for his colleagues, you know how it works best for you, but it’s not really your job to manage their (or anyone else’s) feelings. They’re old enough to handle your ex’s second hand disappointment.
For what it’s worth I ignored a handful of red flags with my last ex, too - it’s not always easy to step back and see the relationship for what it really is, versus what you think it is or could be.