The stuff i used, think it was holts tyre weld, the gas and foam/sealant is in the one can. Never bothered trying but you can get a MTB kit.
Not really anything to go wrong, no compressor to plug into the fag lighter, no valve core removal or trying to pour in sealant first then trying to inflate. Just screw on the can, inflate and seal in one hit in a few minutes.
Without sounding rude, if it is a compressor kit, show your Mum how to operate it, same with seal n flate/tyre weld.
Put some in Mrs Aces car, she can’t get the wheel nuts off so even with a spare she phones the RAC for help, at least with tyre weld she could do a quick fix if possible, limp the car to the nearest services and then wait for a rescue.
The garage that replaced mine, said the sealant reacts with the tyre and renders fixing not possible, i asked if the tyre could just be tubed instead, again not doable. There could be an element of Health and safety rules to this. As you would expect the inside of the tyre was coated in sealant, and it had gone off/dried out, the excess had formed into little rubber like marbles which caused a bit of wobble at speed.
Think it’s around £8 a can, quick and simple and cleaner than swapping a tyre on the motorway 🙂
Oh and the safety bit, your supposed to change the tyre fairly soon in case the sealant fails. As i had a spare wheel, and another can… i drove from Somerset all round western Scotland and back, and had a few months use of the tyre before the sealant failed, then it was a slow puncture, swiftly followed by new tyre.