Regarding your concern that no lower berths were allotted for the three senior citizens in your group, especially with one having a paralysis problem, here’s what I suggest:
You can file a complaint with IRCTC about the issue by calling at the toll-free number 14646 / +917556610661. Explain the situation clearly, mentioning the PNR number and the difficulty faced by the senior citizens.
While travelling on the train you can contact the Indian Railways at 139 and raise your concerns. Provide them with the PNR number and train number.
Tip: Once on the train, explain the situation to the Ticket Checker (TT). They might be able to assist in finding an available seat that can be exchanged for you.