Being disabled should not ruin the chance to explore the open oceans for beautiful marine life and with Scuba Diving, disabled individuals can participate.
It is not common practice but if you search thoroughly then you can be having the time of your life very soon. For example HSA International, deal specifically with dives for disabled people who would perhaps be turned down with many companies.
If you would like further information then refer to their website. http://www.hsascuba.com. Good times are there to be had whether you are able bodied or disabled, everyone has the same entitlement to be human and have a really great diving holiday.