I live in Rome, and therefore have limited experience with hotels here, and only really know what friends and visitors have told me. On the basis of what you have asked for, however, two suggestions do come to mind:

Albergo del Senato: This hotel is very central, practically on the doorstep of the Pantheon. Friends who have stayed there have been very satisfied, and there restaurants all around the Piazza della Rotonda and the immediately vicinity. The hotel seems to be accessible, but I cannot be definitive on this front.

Domus Australia: This hotel is characterised by large beds and spacious bathrooms, and I know that there are rooms specifically designated as ‘accessible’, and there is a restaurant within the hotel. Whilst still within centro, however, it is located more towards Termini, the principal railway station of Rome, therefore less central (in terms of the historic centre) than the Albergo del Senato.

Without wanting to pry into your particular situation, one consideration would be how much mobility (or lack thereof) will be an issue. If you’re able to walk comfortably over short distances, say a few hundred metres at a time, then I would say that a ‘very central’ location would be best, e.g., around the Campo dei Fiori, Piazza della Rotonda, Piazza Navona, etc., such that there are many places of interest and restaurants in the immediate vicinity, in which case I would prefer the Albergo del Senato. If, on the other hand, you will be wholly reliant on taxis to get around, then Domus Australia might be more convenient, as the middle of the historic centre is accessible by taxi only with difficulty: some lanes are too narrow for them, and, just about everywhere else, narrow streets have to be negotiated that, at the height of the tourist season, are so crowded that vehicles can only inch along excruciatingly slowly. Note also that the streets of the historic centre are paved with cobblestones, which may constitute an additional difficulty.