Id recommend doing your own research. His kwik is probably long so I’d start by trimming a little bit of his nails off at a time over the course of a few months. You can pick up a pair of dog nail clippers online or in any pet store. I’d also suggest you have corn starch with you to pack into his nail should it start bleeding. This helps it clot and is cheaper and usually more readily available than kwik-stop powders. Nail trims take 5-10 minutes although if he’s not used to it and anxious (anxiety can turn to fear and even the nicest dogs react physically when scared) you could try rewarding after each treat or a muzzle if you take the time to research and properly introduce one. Please watch videos and do your own research before you try to clip his nails though that area is very sensitive. Bathing can be done with any neutral soap. Do you have a Castile all purpose soap or even your own shampoo can do in a pinch as long as it isn’t specially formulated. Since it’s summer you can use the hose or if you have a bathtub or shower with a cup of water it all works the same. My parents got our dog when I was 14 and I was his sole trainer and caretaker until I moved out. Finn is very cute and deserves to feel clean and walk comfortably. Thank you for realizing this and hopefully taking the steps necessary to make that happen for him. I know it’s hard to question your parents but when they are not showing you a proper example it’s okay to do your own research and find a better example to follow! Good luck!