Hi so is he c/r you on flop? So I guess he is. So  that kind of players who are maniacs you should tighten your pf range. So they usualy c/r you base on flop texture they do that when you cbet on very dry board that usualy dont hit anyone. So in that case you should lower your cbet procent and if you have some showdown on flop Like A high or medium pair or draw you should just check the flop you should check dry boars to. You should bet on flop just strong hands and hand that miss flop complitely. But you should remember if they raise you when you have a hand than just call them on flop and C/R them on turn or river it depens how drawy is board whel if is to drawy and you file like you shouldnt slowwplaying then you must Rereiase them right on flop.  Whell is the player then starts beting into you on every turn, then you can check the flops with your top pairs and then just calling down turn and river. If he see that you checking the flop with strong hands then you can do this later with some bluffs and when they bet on turn into you you raise them with bluff and they belive you cause they saw you before doing thi with strong hands. So remember your pf bet sizing must be disent size like 3x and when you cbet it must be big like 3/4 or 4/5 of the pot so they dont have much space to be creative and bluffraising you becouse their raising size would must be largger now and they will have though disigion to put large money in to a bluff. So I was telling you this when you are in position. You should rearly playing with them oop couse of there agrresion you have problems. In generaly you shouldnt give them a credit every time for big hand usualy your midle pair were be good to call showdown but be smart use potcontrol alot when you are week and pay atentin to theyr bet sizeing you might pick up some reeds and allways ask your self what are they representing with theyr betsizeing and if they are blufing do I stil beat their bluffs. So sorry for my english Im from Slovenia lol.

If he's literally check/raising 67% then stack sizes become very important here. If you're in a situation where you can reasonable 3bet jam over a check/raise then you should probably cbet any decent draw (this is probably lighter than you think, ie KQ on T53 but definitely any open enders, fds, etc) and 3bet jam it over his c/r, as well as most good pairs if the board is well connected. On dry flops you might still be able to profitably stab small with air and fold to a c/r, and you should probably bet/call most of your 2nd pair hands and better. In spots where you think he's simply not folding enough to make a profitable cbet then you should give up with your total air and maybe pot control ace highs and other weak showdownable hands. Realistically if he's check/raising a high percentage but not actually 67%, the advice I gave will apply but we'll still be able to cbet most air and give up, we can bet/3bet bluff occasionally on boards where he won't have many value hands, and we can pot control some of our weaker pairs since we won't be comfortable calling down bottom pair on many board runouts.Try to make use of pokerstove and look at how incredibly weak his range is if he's raising 2/3 of his preflop calling range on a variety of boards, and think about how you can take advantage of his play with each hand in your range. We're going to be making a lot of big pots against this type of player but since his range is so weak we should expect to get in the money good very often and should also expect him to fold to further pressure more often than the average player when we start 3bet bluffing.