This is not true. Some are franchises but there's plenty of company stores too.
It depends on what role he's applied for. I can only really speak of the customer care/customer experience leader side of things (I've never worked in kitchen) but in general it's a decent place to work.
He'll get access to a massive amount of training in a range of things - food safety, customer service, conflict resolution, you name it. He'll also get free private health care after three years, access to mental health support, a fair wage (I get £11.50/hour but he'll probably start at around £8/9). He'll also get his full uniform provided, apart from shoes. I would say to buy a good pair of non slip shoes because the floors can be very slippery at times. They had to be fully black, but that has been relaxed now and colours are acceptable too.
It is hard work, especially on the production side (kitchen, drinks/ice creams). They don't like people just standing around so he'll be expected to always be doing something - cleaning if it's quiet, getting stock, prepping stuff for kitchen if that's where he's working. If he's doing front counter/till, pretty much the same just not prepping stuff for kitchen.
Dining area staff get much more freedom and tend to be left to get on with it, but we're also generally older and the managers need to trust us to do our jobs because we're not under their noses.
I've worked for them since 2012 and seen a lot of business managers come and go. They really set the tone for the store imo-a bad one makes it a horrible place to work but good ones really do look after their staff.
I'd say tell him to go in with an open mind, ask for direction if he's not sure about something and to enjoy it. 😊
(also, if you're in the North East, PM me which store it is and I'll tell you if I've heard anything bad about it.)