Melton1 doesn’t have a favourite, he loves all children equally.
Melton1 Wanted for Pedophilia:
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If Sonny hadn't have been murdered, He would be the new Don.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

Sonny was inclined to be a gangster. Fredo was a turkey. Michael was smart, and could've done whatever he wanted, and actively didn't want to be a part of "the business", at first. I think Vito just wanted him to be happy (though it didn't work out that way).

The way he wanted something better for him than a criminal lif3.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

What makes you think Michael was the favorite?

Vito didn't want Michael involved in the family business and had Sonny not been murdered he would have took the mantel.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

I don't know that he preferred Michael to the others. He just saw that he was the best choice to lead the family.
It was actually a burden he placed on him. Fredo didn't have the sense to be thankful he was passed over.

Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

One of those bodyguards betrayed mike lol. This reinforces my position…constant unknown dangers in a foreign land with little communication by design…very distressing…always waiting to hear your son was assassinated? Far more taxing than a quick realization I would wager.
But I kinda fail to see how any of this revolves around the topic you introduced. Had you argued that fredo was by far his least favorite I think you'd have had an easier journey. Is it your belief that vito loved Mike so much that he'd have bumped sonny to the side as the heir apparent?

If somebody had killed Michael, it would have been known. He had two bodyguards and moved around.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

Actually it could be much much worse. Do some research in regards to a parent suffering the death of a child to that of a child disappearance. Closure tends to help the wound heal whereas the not knowing is an incredible challenge.

Fleeing America isn't the same hurt than losing a child.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

Let's not gloss over Michael's situation as just his involvement in a murder. His involvement meant he would have to flee America to a land where the name Corleone brought serious danger…as Apollonia demonstrated. No clear cut path home as vito languished in hospital. Your's is to compare the grief of a dead child to that of a missing one that could end up dead as well at any time.
And you seem to forget…I'm not picking favorites like you…my opinion is that vito loved all of his children equally

You can't really compare his feeling when hearing Micheal was a shooter to Sonny's death.
The loss of a child would be far more devastating than the Micheal situation.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

He was the youngest and smartest…he saw him having actual power someday… senator Corleone… president even. Fredo was a non starter and sheltered as well we might acknowledge. santino was probably meant to be excluded from it also…but it's sonny…loose cannon hot head…best to be able to keep an eye on him. And tho heartbroken upon hearing of Mike's involvement…it pales in comparison to his reaction to Sonny's massacre.

Why protect Micheal over the other sons.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

It's a family photo. All the children would and should be included.
Vito didn't want his youngest to be involved in the family business…it wasn't favoritism…it was protection

The movie.
At the wedding, when he wouldn't take the pic without Michael and after he got home from the hospital , he gets heartbroken hearing He killed the police captain and the other wop.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

How so? Are we going from the flick or the novel?

He showed favouritism towards Michael before Sonny's death.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

Because sonny was a loose canon and dead and fredo was… well…Fredo

Zip it or you'll be sleeping with the fishes , like Luca.
Chopper: I'm just a bloody normal bloke. A normal bloke who likes a bit of torture

Nah…that would probably be Croft

You’re the Fredo of filmboards