my dad from him...

I can't think too much about it because if I do I just imagine a young boy wondering why his mama had to go and it breaks me every time...

I'm so so sorry for your loss... It sounds like you're doing great as an uncle. please continue to be there for him, because he is going to need as much guidance and love as he can possibly get. Nothing will replace a mother's touch, but we can do our best.