Everyones situation is different and unique, but here are a few general resources, videos, and demonstrations to hopefully give you ideas on how to adapt crochet to your personal situation! Most of these resources assume you already know how to crochet. Despite my best efforts, not all these resources may be accessible.
I am not affiliated with anyone or any site that I link to, nor do I earn money from any of these links.
There are a few ways I've found how to crochet one handed. Some versions require some kind of modified hook.
There are a few techniques you can use to hold the yarn and the hook in one hand and crochet that way. Sadly I couldn't find any in-depth tutorials that don't require a second hand, but here are a few demonstrations I found.
One way is to use a long tunisian hook, or a regular crochet hook securly taped to a long knitting needle, wedging it under the arm you will not be using, or between your legs, and crocheting with your other hand. This way is demonstrated over these linked videos.
While I cannot find somewhere that sells crochet aids, or a full tutorial on how to make one, they are fairly simple in design and can be made at home by someone at least familiar working with wood. In essence the aid is a block of wood you can clip to a table or another solid object, and a vertical block of wood with a hole in it where you can put the hook in. Preferably with a way to tighten the hook into the hole so you can swtich out hooks, or with the hook glued into the hole.
Another way to crochet is to use pre-looped yarn to finger crochet, as demonstrated in this video.
This is one womans way of adapting to crochet with missing fingers.
This is not a tutorial and more a demonstration on one womans way to crochet with no hands.
Here are a few ideas I've found that may help when holding onto a crochet hook or tapestry needle is difficult.
Hadley is a recource for vision impaired friendly activities and resources. You do have to make an account to get access to all their resources, but I think it is worth it.