It means you miss your Dad very very much and this new relationship will flourish because you feel an affinity with the boy as he has something in common with Dad. Not a sound basis for a relationship some sceptics would say, but what if your Dad had sent him to look after you and it was his way of letting you know?
Coincidences like this sometimes resonate with you for various reasons. If you find this particular coincidence has meaning for you, then that meaning is valid. Don't be put off by anyone telling you otherwise. The world is a very strange and complex place. What appears to be nothing more than blind coincidence to one person can hold profound meaning for another. Each person's take on it is equally valid for him or her.
I dont even think this is a particulary a coincedence. He's got the same initials - so what?
If he had the same name, was born on the same day, went to the same school as your dad and they both had a dog called Casper - now that would be a coincedence.
As it is, just having the same initials doesnt really mean anything at all - sorry!
It is a coincidence, just not a spectacularly unusual one. He could have had any combination of letters for initials, so the fact he had the same two as another person, and in the same order, is coincidental. Whether that is important to the individual, as I said in my earlier post, is up to that individual to decide.