I don't think it is a breed specific thing, to be honest. From what you have said, it sounds more like a 'kids and puppies' thing to an extent.
Kids and puppies are a BAD mix. For this reason, I only allow my own puppies with my younger two children (7 and 4) unless strictly supervised, (as in my focused on them 100% of the time, not just me there but cooking tea, washing up etc) until both puppy and child know how to behave appropriately around each other. Puppies jump up. Children do fun things (for the puppy) when they jump up, like wave their hands around and scream. So the puppy has more reason to jump up and get excited. I would imagine that is why he is 'targeting' your three year old. Unless your child can be taught to turn their back and fold their arms if the puppy jumps up, do not allow the puppy near the child unless you are holding the child, so the child can't inadvertantly encourage the pup's bad behaviour. Keep toys away from the puppy, as they can be dangerous to him apart from anything else.
If you love the dog, and feel that you would be prepared to keep him no matter what, or no matter how hard work he became, or what problems came up, then it will work. But do be aware that if you are finding it hard now, it will only get harder during adolescence. I would no more give my dog up than my children. That is how it should be as far as I am concerned.
It doesn't sound like you are going to a training class? This is an absolute must. Look on
Puppy training classes, Puppy School is a network of UK schools for training young puppies. for a good one, and be quick as I think 20 weeks is the cut off for starting puppy classes. There is also a book called 'Puppy School' by Gwen Bailey, another book called 'The Perfect Puppy' by her, and a book called 'The Culture Clash' by Jean Donaldson. ALL are essential reading for any new dog owner, IMO. Thinsg will nto magically work out, you need ot put in a LOT of hard work for it to. With any breed, not just a springer.
What is your dog's breeder like? Are they available for a phone call if you run into problems at any time? This is a great help to most people.
Personally, I think his family have a cheek assuming you cannot handle your dog. They might be better placed offering more constructive advice. If it were me, I'd do my damnedest to prove them wrong!