Calprotectin and medication questions

My 12yo son was diagnosed with Crohn’s last year. At the time he was quite sick and his calprotectin was 7100. His doctor put him on a steroid while we waited for insurance to approve inflectra. After starting inflectra and then raising the dose, he felt so much better. He gained weight, grew, was less fatigued, etc. Labs improved with that and iron infusions. We just learned he’s building antibodies to the inflectra and it’s essentially running out too fast. Since his symptoms had improved on it, we opted to try sticking with inflectra but adding methotrexate and folic acid. He had some weird reactions, including numbness that came and went in his arms and legs and hot/cold flashes. These went away after discontinuing the folic acid. For two days after taking the methotrexate, he had extreme fatigue and nausea that kept him home from school. His calprotectin yesterday was 400 which is way better than last spring but still not great. We’re now looking at switching to Humira but trying the methotrexate once more just to see if the symptoms were the drug, Crohn’s being weird and active, or something else. Our pediatric GI is the absolute best and quick to answer all of my questions, etc. but I also definitely value the various experiences and perspectives of the Crohn’s community. That said, 1) Has anyone ever experienced any reactions like that to those drugs? 2) Has anyone developed antibodies to a biologic and had success with another? Did you need methotrexate with it to work? 3) Is normal calprotectin even achievable or am I hoping for something that won’t ever exist for my son? Thank you in advance for your shared experiences. :-)