Play against agressive half full buy-in player at 6-max table

[Indomitus]

Hi there!well i had seen one guy at low limit NLholdem 6-max tables.but i fancy it could happen on other stakes too,so i decided to post it here.so for example at NL100 he had buy-in 50$.played about 30/20 in 500 hands.and if he raised-he raised more than usually people do-he raised to 5$ at these stakes (so 5bb raise).He seems to be a reasonable 4-tabling player regular.But his play with that half buy-in and larger than usually raises confuses me.So what could be the best line to play with that guy?and which hands preflop it is worth to play with him?