Now letting him jump back into your heart? That may not be something he'll feel safe trying to do for some time. He's still testing memories of the life he lost. There's a big divide to cross if he ever actually wants to live on that side of MLC again. And for him, there's no clear bridge to cross. He will have to build one and he may not have healed enough or have the strength for a while.
You may have to decide when and if you healed enough and gained the strengt to help build a bridge. He may stay comfortable for a long time with just getting to be Dad again public and family events. Its like he is over on his side of the crisis but trying to see life on the brighter side.
No pressure, so don't create any for yourself. Don't form expectations and tests too soon - as failure could be built in. Expect to find a friend if you want one and behave like one. Friends can be wonderful and sometimes they grow into much more.