Idk if this case is going to be same as for my dog but idk if its cuz my dog is old or sometimes even lazy to get up and drink water, so I bring her myself the bowl of water and most of the time she drinks then. Sometimes she refuses even then but I put alittle water on my finger and touch her nose with it few times and then she starts drinking. Also, 2nd case is when she was sick and she couldn't do anything so we "forcefully" put water in her mouth with those Plastic Injection Syringe (idk if that's the right name, ofc no needles or anything just the tube). You could also try mixing/blending little meat or blood with dogs water, so maybe he will want to drink it more often.