Having baby at 40 is not a problem. I have my first son at 34 and my second son at 41, both are natural delivery - no problem at all. 1st son took 5 hours from delivery symptom to birth and the second took an hour less. Actually my second son (now 1 year old) is smarter than my first at the same development stage.
My elder sister has similar case as mine: 1st son at 29 and 2nd son at 39; the 2nd son is a lot smarter than the 1st. 1st son can hardly finish the first degree, but the 2nd son is considered as gifted.
I am the last kid from my mom: she gave birth to me when she's at 39, and I am of the strongest build with the best academic performnace amongst the siblings.
Tell your friend: no need to worry about quality of the baby anymore. Check everything to make sure the baby is not defective, then she can accept the baby as she wished.
The most important thing she has to worry about is the delivery process: obseteritians may advise her that delivering 1st baby after 40 will be more difficult because the muscle/ bone joints are harder due to the age - she may be suggested to deliver the baby by c-section (surgery) to reduce the risk.
The last thing she has to worry about is the figure after birth: it's true that it's hard to keep back the good old shape when you are aged - skin/ muscle has lost elasticity/ recovery and metabolism is a lot lower. But your friend will be already 40+; she may not care about that anymore!
Just pm me if she need further help from an older mom than her!