When Josh receives a mysterious phone call from the hospital by his estranged son, he must decide whether to sign a medical agreement that will alter his child’s life forever.

What is the action that will carry your protagonist through 50 pages of ACT 2?

He must WIN something/someone

He must STOP something/someone

He must RETRIEVE something/someone

He must ESCAPE something/someone

These 4 actions will help you think about what your character will have to do to get what they WANT and eventually what they NEED.

Everything you have written could take place in five minutes.

A guy receives a phone call, goes to the hospital, he's told he must sign a paper, He either decides to sign or not to sign, then the story is over.

The reason I point this out, because it's difficult to visualize a story from the logline that you have written.

In other words, I don't think the logline conveys to the reader the story that you wrote or if it isn't written, the story that you visualize in your head.

In addition to what Scott said, I would add that "deciding" is almost never a compelling story element in itself (apart from films like "12 Angry Men" where the decision is the story). Normally, the story is what happens after the decision has been made - especially if we (the audience) feel it was the wrong decision. Try writing the long line from the POV of what happens after the decision is made.

On another note, by using the word "child" to describe the son you imply the son is a minor. Then, by saying the father is estranged from the child, you imply someone else, probably the mother, has custody over the child. If that is the case, then the father cannot legally sign off on any medical procedure. Likewise, if the child is no longer a minor, the father also has no right to approve of anything.