Okay, this link is for age 3 and above BUT I feel like with the little ones, time passes quickly, and before you know it, he'll be three. My daughter will be 3 in 3 months, so, I am holding onto this link until then. In any case, it's the best I have found so far.
The other thought I had was to give small doses of the Primal Defense in powder form perhaps by mixing it in food. Don't know how it tastes. My daughter is most willing to take Omegazyme (by the same company) straight up and it's also a powder. In any case, a probiotic may be benefitial to him to infiltrate his GI tract with the good bugs and thus helping him fight infections in general.