Toddler 3,5 years old has very hard time sleeping

Hello, I am looking to get help for my grandson 3.5 years old, who has a very hard time sleeping. I am looking for constitutional remedy according to totality of symptoms, as I can get a combination remedy myself, but prefer to address deeper issue if there is one.

Ever since birth he cannot settle to sleep easily, can wake up during the night often multiple times, sometimes screaming loudly. He gets rocked back to sleep, only to wake up again a few hours later. He has always and to this day resists having an afternoon nap.

His birth was very good and non-traumatic, he was breastfed on demand until 2.5 years old, has attentive parents who raise him at home (has not been to daycare so far).

He was born with an undescended left testicle and soon after birth developed an abdominal hernia. I looked up those two symptoms to find a remedy that applies to both and located Aurum 200C. I gave him one diluted/wet dose of this. Slowly the left testicle almost descended but can go back up sometimes, so its not really fully down yet. The abdominal hernia resolved itself over the next few months after the one dose of Aurum. No other dose of this remedy was given. I tried giving him one dose of Chamomilla 30C to see if it would support him in sleeping better but it did not give immediate nor lasting results. Last year my son took him to a local homeopath who gave him Pulsatilla 30C, a few times. They did not see any real difference with this either, so I thought I might try get some help here.

When he was slowly introduced to solid foods he would try greens, berries, and other varieties of food, but over the last while all he wants is floury things such as pancakes, toast, rice with olive oil, some chicken, perogies. etc. His dad makes him good homemade soups of which he has little bit, but if he has french toast he will eat very well.

He is very thin, a brunette boy, somewhat small for his age if one compares to other toddlers, dark hair and eyes. His temperament is very sweet except when he disagrees with you, ie if he wants to do something a certain way he will insist that you do it, but not get angry necessarily.

The main symptoms right now is that it is a very big struggle to get him to sleep, and when he does its not uninterrupted, he will wake up often. The times when he slept through the night are few, ie if he is really really active during the day.

His parents take him out to the park every day and he plays well with other children but I can say he is fearful of new things. He needs to get to know people and situations really well before he can get comfortable to let go and have a good time. He is an excellent conversationalist once comfortable and his doctor even mentioned that he may need a school for gifted children. His parents are not in favor of rushing anything and want him to be healthy in all aspects of his being.

If he gets really mad he can hit his mom or dad because he is so frustrated that they try to get him to sleep. He says, no we will not rest.

To recap present symptoms:
left undescended testicle
refuses to sleep
loves carbs
can get very angry if told to sleep or eat more variety. Also hard to change his mind if he says no more food.
At 3.5 of age not fully toilet trained, for example he worries when he comes to my place and only settles to play well when he I put on the diaper. Then he relaxes and he gets to playing carelessly. He is a very thinking boy-always something in his mind.

I really do appreciate for help/suggestions as to how to go about here. I read that Calc Carb 10M plus Thyroidinium 30C for the testicle, but I dont want to do any harm due to my limited knowledge. Thank you so much