"I am afraid that my son does not remember his grandmother."
Translation:Ho paura che mio figlio non ricordi la nonna.
"ricordi" is present subjunctive form of the verb "ricordare" for 1. 2. and 3. person singular https://en.wiktionary.org/wiki/ricordare#Conjugation
Subjunctive is used in secondary clauses when they are introduced with "che". http://www.italymagazine.com/community/post/italian-lesson-when-use-congiuntivo-subjective
Should this really be ricordi and not ricorda or is it a mistake??
Not a mistake. It is present subjunctive, but I do not understand why it is here, before subjunctive is introduced.
Subjunctive is probably one of the best things Italian language have, but it's really difficult to learn. I think that at least half the Italian population can't use it correctly... So don't worry: in case, you're not alone! (I'm a native speaker)
I think the correct form should be : Ho paura che mio figlio non si ricordi di sua nonna. the verb here is : ricordarsi di qualcuno: remember somebody