What?!? You saying hunters can't take a 45 degree heel? Hmmm, I think that's not correct. we should NEVER insult someone's boat on this forum and tell them to buy a new boat.
Although I would never sustain a 45 degree heal because I and most importantly my "significant other" in my life don't like it. But that's just us. (I love her and want to make her as comfortable as I can.)
The damage, looking at the photos, looks old to me and sailing just made the repair job show its weakness. One wonders if the original damage was caused by over torquing the standing rigging or some sort of unrelated accidental damage years ago. From the photo it is not clear to me if it's actually pulling out, or is the crack just affecting weather sealing? Probably need to see it in person to properly evaluate the damage and figure out the original cause. But I have seen people over tighten rigging on a hot day. One guy told me he was working to change the sail shape and had the mast bent considerably. I don't know about the wisdom of that but that's another discussion. In that case it put too much strain on the fiberglass rear deck and caused leaks as the back stay chain plates pulled the deck way up.
But that's another story. Just saying it is not clear to me from the photos what caused the damage initially and I think understanding that is important. But while I have not spent time sailing at 45 degrees, it seems unlikely this alone would cause damage like this if it was solid to begin with.
It would be probably be wise, since it is affecting your mast, to consult and pay a local experienced professional like a marine engineer with sailing experience for their opinion. If you pay them for advice they may be willing to advise you on how you can repair this yourself. Then pay them again to inspect your repair and then you may have to redo it or be good to go.
It's a DIY if you know what your doing, not the sort of repair that's a learn as you go. Hunter is not the sort of boat that's built to take that kind of heel over an extended time. Hunters are good boats but have their limitations, if that's the kind of sailing you like, get a boat capable of blue water sailing. Not having seen the job I couldn't estimate the repair cost, but it'll be substantial.