It is sad to acknowledge these limitations of bitcoin and cryptocurrency as I know it now, to not only be limited based on funds but handicapped situations of individuals.
Bitcoin was not invented by satoshi to solve the financial problems of everyone including handicapped persons. It's aim is to give financial freedom to all that embrace it. The blind man, though unfortunate would not be able to access bitcoin and blockchain related services. Handicapped persons have more problems to find solutions to than trying to join the financial freedom struggle with it. They just deserve to be in a care home, fully taken care of.
If they are interested in bitcoin, they should look for someone who will help him to access bitcoin if he do have a money to invest, a relative will do.
I'm pretty sure that blindman have someone to rely on that is helping him in everyday lives, and that person can also help him to explore bitcoin.
If they deserve to be cared and loved, then they also have rights to invest on bitcoin no matter what situation they are in in life.
Being blind is not a hindrance for him to invest in bitcoin if there are other ways to deal with it and if he is determined to explore it.