How friends does a little boy need?

Lately I've been feeling bad because my son has only three friends his age and two of them are twins.

I know that the term friend is stretching it a little for a two year old since he treats everyone about the same. He smiles hugely at them. He'll look them in the face and talk to them. It's even odds whether the words will be English or his own special language. Then later he grabs their stuff.

And then on top of that, he has an older sister who says she has "so many friends" (her words)
Of course we have to play with them, or she tells me "[X] isn't my friend anymore, because I never see her/him." Yes my daughter knows the exact guilt-inducing words to get me out on a playdate.

But sometimes I feel my son could really use more playmates nearer to his own age. Yesterday at a park he and an eight-year old boy were wrangling over a plastic spoon. My son won, because the eight year old just felt too ridiculous fighting with a boy, the size of a one-year old, who was yelling loudly. My son typically deals with older kids and this technique works for him almost always.

I want my son to learn that while it's good to hold on to your stuff, but you can't win all the time with this technique, nor is this a good way to win friends. His friends hold tight too and they just walk away holding the toy triumphantly.

I just realised I had the same concern about my son last year. And then he had another relapse and secondary infections and even if he'd gotten more friends, he wouldn't have been able to see them since he was immunocompromised. And I'm not sure where in the past three months of actually being able to see other people, I can it all. And I thought maybe this is just a proxy for my worry that it's been so long since we've been out in the world that I've forgotten how to make friends. And maybe my son actually doesn't care that much as long as we see people.

At age three he'll go to preschool (if he manages to stay off chemo and steroids long enough to get his shots). I worry he'll get picked on, because he's small and grabby. Maybe I just need to get out more and stop worrying so much.