Which is the correct verb?

IT is high time that someone gives him...

I give
you give (sing. & plural)
he/she/it/someone GIVES
we give
they give

'is' is present tense, as is 'gives' and 'gave' is past tense.

The simple present tense uses the base form of the verb (the infinitive without ‘to’) except in the third person singular. The 3rd person singular (he, she, or it-- one person or thing) ends in -s or -es (talks, goes).

Both are correct, using the past tense form 'gave' simply puts the notion into a more tentative/unreal/... situation.