My son lived in the same complex as me and he got evicted. Is he allowed on the property to visit me after this eviction (Ohio)

You should check with the complexes rules. I don't see why he wouldn't be allowed to stop and visit for a few hours or a day provided he wasn't evicted for his behavior or serious problems.
The complex probably would not appreciate you allowing him to stay overnight though.

They gave us a ten day notice to leave the property because ha visited. Can they do that?

Check your lease and then challenge them on it if it doesn't say anything about this and appeal it if you can.

Why was he evicted, was he an illegal tenant, did he violate some other rule. Was he given a criminal trespass warning.

Did they tell you he could not come there.

The visit ? Was it over night or just a few hours during the day.

He was evicted for non payment. No tresspass warning was given and he visited for about 5 hours with my grandson

Definitely check your lease about this. They are being quite unreasonable about him just visiting. I can see nonpayment but I can't see him being barred from visiting his relatives and you getting a 10 day notice. Just how big a complex are you in and is the owner on premises or just a complex manager?