Is hydrogel for obesity safe to take long-term?

My teenage son has struggled with his weight his whole life. Although I have tried to cook him healthy meals and encourage him to exercise, he hasn’t lost much weight at all. As a final resort, I took him to see a physician. The doctor recommended that he start taking hydrogel pills. While I’m relieved that we have another option to try, I’m also very worried about the side effects that it can have. Is it a treatment that is safe to take long-term? Or should we look into a more sustainable treatment plan? Thank you in advance.