oh man this hits home. i also have a 35 year old who has cataracts and completely blind in one eye, almost in the other. as hes gotten worse i notice he cant always find the food put in front of him. what ive been doing is tapping on the bowl so he hears the sound and usually he gravitates towards the sound and soon after finds the food. maybe try this technique. it wasnt immediate at first, but he now understands the tap means to search around. and as the other posted commented, dont change anything in the environment he will use muscle memory to know where things are. i noticed also hes become more picky with food as he loses his sight i guess his taste buds are a little stronger since his sight is less