Hello there again,
So focus on the positives, it’s important.
Here is the deal IF you want ALL the night to be good and sleeping through, not just occantianally nights then this is the road there. It WILL take work from you parents for a couple of weeks. The result will depend on how well you as parents are doing with the cure. The baby is only responding to your actions.
Figure out if it’s worth going for, if the answer is YES then carry on and leave the doubt behind. The good nights will come.
To your questions:
1. It’s not just the milk in the night who will sustain him over night, it’s the complete food intake during the day. So make sure he eats a lot of food through out the day, not snacking but proper food at mealtimes. Milk milk is still just fluid and won’t sustain you, perhaps a banana before bedtime instead if you think is needed or something else he will eat properly.
2. Is he given water with every meal during the day? If he is he does not need to drink during the night, offer him some with the banana just before bed.
Reflection: so because you gave in and one night picked him up and another night gave him water he is confused at night still. He is not convinced yet that what you should do at night when you wake up is just roll over and carry on sleeping. That is why he cries because he knows eventually one of you will come in and something will happen. If you only response to him at night is the jingle he will understand much faster.
3. It takes at least 4 days a and then a follow up week but it is entirely up to how the cure is executed. Obviously we are all beginners as parents, I’m a mother of two and baby number two was much faster to cure because I was a bit experienced by then and new what didn’t work or what slowed down the process. So keep going, it can be two-three weeks the more times you give i to him crying and doing something that is not jingle/fan/buff the slower it will be.
4. So a fan is a firm pressing down with a hand. It should act like a message as to help him understand that standing up or wiggling around will not make you fall asleep. But is should be with love and a pressing rather then pinning down. If you struggle with it perhaps buffing is better for you since your boy is a bit older.
I have to advice that loosing hope when you have a set back isn’t helping, instead think:
“Ok, he struggles, I’m here, I know what to do, we as a parent team have prepared for this we will NOT let you down. You can trust us, you can sleep.”
You know there will be set backs, it’s a part of their learning process so see it as an opportunity to teach what he should do when he wakes up at night. Sleep. Every set back is a chance to teach him so that the next night he knows what to do. He will not stop waking up at night but he will stop crying for you because she will know that falling back to sleep it what he is supposed to do.
Chin up, put the teaching hat on and carry on. Attitude is everything, if you stay positive this will be much easier.
Hugs Tin
Im glad my husband took the lead, as I am too weak 
and give up easily
