I think there are buggies going up and down but I suspect any form of transit assistance may need to be pre-booked via the airline.
https://dohahamadairport.com/faq/i-n...ial-assistance
There is also the option to pay for a premium Al Maha service, although for transit which guarantees queue jumping at transit security if you get directed that way.
https://www.al-mahaservices.com/almaha#/transit
There are travelators once on you get into the main concourse, and there is the monorail system that runs the length of the C section of the terminal. I can't recall if there are travelators on the upper level walkways to assist with the journey from the gate towards the transit security.
I guess it might be one of those things where if you are in doubt whether you need it or not it's probably better to book something otherwise you can end up worrying if you can transit ok. You might avoid transit security, and leave from the adjacent gate, or you might need to go through transit security and go to the furthest gate (which might be 20 mins away for a normal bodied person).