Hello everyone.

Today I want to learn about the subjunctive mood.

Is the following sentence grammatically incorrect?

(1)The little child is lonely; he would be happier if he had someone that he
can play with.

Some reference books insist that we should say "could play with" instead of
"can play with". But some other grammar books argue that there is no need to
do so.

I have thought that (1) is correct. Am I wrong?

Thanks in advance.

SIRAISI Tomio