I just wrote a massive post about how worried/guilty I am that ds and I have lost our closeness since ds2 was born and ds1 started school (he's now in Y1) ... and now I've deleted it because it was seriously incoherent and rambly.
Basically though, I want to know what the signs are of a good/healthy parent-child relationship at this stage... or, conversely, the signs of a bad one.
My 5yo is often quite moody and prone to tears, seems FAR less eager to please than he used to be, is much less effusive about loving me than he used to be...the list goes on. I feel horribly guilty that my postnatal depression after ds2 was born might in particular have caused this, along with the fact that I feel so drained all the time dealing with my demanding toddler.
Starting to ramble again so I'll cut this short..!
I wouldn't worry about how yours is behaving. My two five year olds are twins and are very whiney and bratty. But they do grow out of it.
I know that with all of my children, I can tell we have a good relationship based on the little things. For example we will have nice, little conversations; play games together and they show affection towards me, even if it is to get things out of me.
After having my DD1, I felt as though DS1 was a little left out. But I made sure we did things together and when I focused my attention on them, it would be to both of them at the same time not one at a time. This has also helped my children have a close bond with each other.
I think perhaps you and your son have a better relationship than you think, and I wish the best for your family.