My friend's son has delayed his milestones. He is two but still not walking yet. He also has a lot of digestive issues and hardly makes eye contact. Could he have autism? I suspect it but I don't want to upset my friend.

When the conversation about your friend's son comes up, you can in a subtle way suggest that it would be a good idea to see a doctor and rest all the doubts in mind. It may be that everything turns out fine, but at least all the stress related to it would be settled. I think by suggesting to see a doctor is a good advice that you would be giving your friend, and if it upsets her, you should not take it to heart. Being a mother you would know how it feels if something is not going right with the kid. It is fine, and you should still suggest your friend to do what you think is right. Upsetting your friend is just a minor thing, just imagine, if your advice is taken and it really helps the child, how happy you would be to see the kid developing find. Check this link and see, and check if the kid shows the symptoms, and what you are concluding to is actually right or not. https://www.autismspeaks.org/what-autism/symptoms https://www.autismspeaks.org/what-autism/learn-signs

Just tell her to have his son checked by a Developmental Pediatric to see if there are any delays. If there's none, then thank God. If there is, then thank God, at least now she knows and appropriate intervention will be done.