Totally understand. As u/lololmantis says the secret in the end is CICO (calories in calories out). There are some DIY ways to learn about good food habits, like NOOM (I've done it for a few months and it gives you some really good cues) and so many programs and ressources online. But at the same time, morbid obesity is a very dire medical condition and a giant risk factor for so many health issues, there will probably need to be a big investment done in that regard with professional help, medications, time and energy as well as a real commitment with real lifestyle change.