With 405 points, unless you are FST candidates, you friend might have a chance but if he's been waiting since 2017, it is clear that he's FSW candidate. The cut off points might be roaming around in the 400s before 2017 but the lowest cut off score for the last 2 years was 413 in draw #65 31st May 2017. Which is 8 points higher that your friend's score and the cut off score has been higher ever since
So, please don't be misguided by the agent and keep trying to get higher IELTS score. It make a lot of difference if he get L8 R7 E7 S7.
Additionally, ask his wife to do IELTS as well and get her diploma assess for ECA. Even if his wife only get R4 L5 S5 W5, she will contribute 4 points for IELTS. If she get 6 each in IELTS, she will be rewarded 12 points and and if she gets L8 R7 W7 S7 or more in each skills, she will be rewarded the highest points which is 20points
Furthermore, if her diploma is assessed as equivalent to even only 1 year diploma, she will get rewarded 6 points. 2 years diploma 7 points.
Her foreign experience won't add any points even if she has one. Only experience gained in Canada is earning points as a spouse.
All the best.