For his serves, can't help you much there..for kick serves, try to catch it before it gets too high on you or let it drop if you need too. For slice serves move in and catch it at an angle moving forward, so you're not moved as far off the court. For flat serves, just sort of (short backswing) punch it back, you'll get plenty of power from the serve. Don't forget to keep your momentum going forward.
For his slices hit loopy topspin to his backhand side, not an easy shot to slice back effectively, if he slices expect it to be a sitter slice and not skidding (could skid sometimes). For his flat shots..try not to hit weak balls and let him move into the court to hit a flat shot..if he does its higher percentage shot for him..if he hits flat shots from the baseline well and consistent, just keep your backswing short and hit it back in with topspin so you have good margin of error and still effective because you just use your opponents pace. If his topspin is getting above you, catch it on the rise or let it drop and hit.
![[d]ragon](/data/avatars/s/26/26312.jpg?1574364787){kind=avatar}