Firstly hi and welcome Cheetsey,Sam/Pam
I'm afraid i have no medical advice to give you,sorry. But totally understand how you must be feeling in the circumstance that you are both in, it sounds optimistic that his liver with your care could well recover and even if not if he's happy and in no pain and able to live with medication well that has to be good
We have cats that we sometimes have to medicate with tabs and trust me a scared cat can be just as dangerous as an angry cat,ours won't take them lightly either,i usually scruff our worst cats firmly by the scruff of the neck and hold them in a way that they have to tilt their neck and gently push the tab in the middle of their mouth on top of the tongue(so they can't hide it or hold it to spit it later)if i don't manage it 1st time i leave them and try again later-so far so good
It's only natural for your head to be in bits and to feel up and down,take as much of the positive from your trusted vets opinion and go with that,Sam will more than likely surprise you in no time and he'll settle into his new home and be getting up to all his old tricks and probably invent new ones,as long as he is getting some water don't worry to much as he'll get hydration from his food,to check if you need to rehydrate him just scruff his fur near his neck,if it's slow to fall he needs hydrating if it falls as your skin does he's fine-this way you only have to hydrate him with a syringe when you have to thus less distress for him,hope i've helped a little
Bear in mind also that vets are like doctors in that they mostly give you the worst case scenario til they've all the facts,a standard practice