Geonz, if this guy is quite special, his mom very likely had a lot to do with that.
I think your idea of putting something there for him for when he gets home from the funeral is a good one.
I lost my mom last year, and out of numbness and self-protection, I held it together through a SRO funeral. After having to keep everything going through her care and the arrangements, and with my dad...it took a long time for me to unwind at the end of that day, and really let go like I needed to.
I had a dear cousin sit up with me until almost midnight, when the dam burst. It really helped me un-freeze to have a tender presence there for that. And, my mom was my best friend. You don't get over that loss in a hurry. For me, the small remembrances here and there in daily life, and the small gestures from my friends, letting me know they realized I wasn't "over it," as time went on, really helped (and still help).
Every person grieves differently and needs something different. In my case, I needed the TLC after (and ongoing) when the hoopla of funeral and condolences died down. That's just me. It took one of my brothers months to admit how hard he was grieving, though.
The hardest thing for me was when people stopped asking about it...as if it was all done. But, for my brother, he wasn't ready to feel his feelings yet, and it just annoyed him when people asked. People are so different.
But, if you care, show it. Just be authentic. He is lucky to have a friend like you.
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury