Help With convertible top please

Someone gave your Mother in law bad info. It needed to learn what it feels like to be latched from day one.
To get you on the right track: Never leave a top down for long periods of time. Put it down ,enjoy it, when your done, put it back up. Never store it down,"not even overnight"
The vinyl will get a memory faster than you know. As it ages it shrinks, gets stiffer and harder to work with.
Now to your issue: Find yourself a couple of helpers. Have someone stand outside and force down on each corner while you or someone latch that hook. Do both sides this way. It'll go!

Then leave it up and latched for awhile. Let it sit in the sun as much as possible. It will need heat to soften the vinyl. Heat lamps or large Halogen lights left on over the car can help.

Once you get it back up and latched be patient, it should get easier in time.

Good Luck

Here's the official ford manual if you have any questions.
top info.pdf

Also, a hand on top of the convertible top where it bends right above the drivers seat pressing down while someone also pushes forward on the frame from the rear tack bow should help it line up and reach the front header.

As long as the top was made in the factory correct single texture pinpoint vinyl it should give way w/a bit of heat and some muscle.

However, if the top was tacked to low in the rear below the window it may call for some adjusting. If the install was botched you may have to find a new shop to re-tack the rear and allow for a bit more slack. The issue being, when you un-tack the top it will leave small holes in the top. However these can be filled easily enough with a black silicone.

G'luck and let us know how it goes!