Thank you all for all of your support. I did an Amazon search and found this: http://www.amazon.com/Kids-Preferred-90927-Baby-Doll/dp/B004KS2T84/ref=sr_1_1?ie=UTF8&qid=1402679491&sr=8-1&keywords=toddler+boy+doll
We just found out we are expecting #2! Bug will be 21 months when he is born. I've seen recommendations to get a baby doll for him to play with and have his baby to carry and take care of, and also to teach him to be gentle.
DH's reaction to this was "Does it have to be human?" (as in he would be more comfortable if DS took care of a puppy than a human baby doll)
Also, if a human doll, any recommendations? Obviously, we want something as neutral as possible.