Honestly, my horse was fine because the most I would ride him was maybe 3 days a week (4 or 5 days a week every once in a while), and frequently he’d get ridden maybe 1 or 2 times a week and even NO times a week here and there depending on weather and life, etc. So, getting “turned out” (he was always out anyway) was no big deal to him.
I’m sure some horses might not take to the lack of structured work. Mine definitely has the brain for it. After years of not so much as putting a saddle on him, when I started back he just stood there like it’d been happening every day. But…he stood there like that when I very first broke him as well, so that’s just his nature. He’s never been an unrideable nut job.
You’ll just have to see how your guy is. Even if he’s not quite like my guy, it might be as simple as working him in a round pen or on the lunge for a few minutes to blow the cobwebs off of him and see if he has any silliness in there. If he’s a good-minded fella, I bet you’ll be pleasantly surprised.