This isn't going to comfort you muchly, but given the importance of how delicate without any concrete evidence, sharing with you may help.

I went through the same thing. I noticed his presence Appearing at totally random places, places I've never seen him before , to the point I almost stopped someone just to look at him. *almost*

It fades away as we start making new memories. I understand the confusion and warmth hinted with shock. But that's our memories tricking us.

I believe the best approach is to acknowledge his death, afterlife, etc..what ever keeps you going in life.

You've lost someone and sometimes we simply need to forgive ourselves for the not so good times shared.

People most certainly pushed me away from that time when Richard passed at just 23 years old and I was thankful for not dwelling on it, however still never fully processed what magical connection to his memory when he was 'spotted'.

Contrary to what I've said. I strongly recommend you and only you should donate any of his 'sentimental' possessions. This protects you from ever 'visiting' the past, let's face it, we don't need a constant reminder...

I held on for ~15 years. Give or take some minutes. I kept looking for a meaningful answer to it all. And this is what I found.