The thing about allergies is that what is going on is that your own immune system is "over reacting" to whatever it is that is triggering it (pollen, food, chemicals, whatever)... so most of the remedies are either something that LOWERS your immunity altogether (hence the risk of sinus infection from some allergy medicines) OR they work to "desensitize" your system to the trigger by giving you tiny amounts over time.
I haven't found anything myself to be 100% effective and the remedies which have been the most effective for me do carry some heavy side effects too.
Probably the "best" thing at this point, particularly for your little one, is to try using the local honey to help desensitize you all to your local triggers.
Another "simple" thing to do is to try to avoid some of the ones that are avoidable. Certain foods (fruits and veg) have the same family of proteins as some of the plants and flowers that are triggers... among the theories involving this is that perhaps by avoiding eating those things, it will help lower the allergic response to things less easily avoided (the blowing pollen). For example, if you know that you and your husband have a reaction to birch pollen, it may help lessen the symptoms if you avoid eating apples, apricots, bananas, avocado, peppers, etc etc ("whole" list on that link).
Conversely, you may experience symptoms when eating those things that are linked to that pollen allergy, you may get a mildly "itchy" feeling in your mouth, throat and ears. So, pay attention to whether you are having these feelings and it will help you to figure out what pollens are bothering you.
Unfortunately, only using my own family as example, heredity isn't a "guarantee" of knowledge regarding what your little one may be allergic to either. Some of my family members have allergies to animals, some (incl me) do not have this, some of them have this sensitivity to certain foods but don't seem to suffer from hayfever so intensely and others it is vice-versa... and for many of us, it is different things. HOWEVER, the older I get, the more my triggers are very similar to what bothers my father. (My mom has none so it's hard to say... I do not seem to share the same triggers that I know her brothers exhibit though.)