I (23 F) think, antidepressants are making my boyfriend numb (20 M)

My boyfriend (20M) had anxiety his whole life, and 3 months after we met he was diagnosed with depression as well. He was put on sertralin. He said it made him feel more in control at first but with every dose change I feel like he lost more and more of himself. He has been taking them for 4 months now. He is not exactly depressed, he used to talk about feeling trapped and hopeless, lately he just looks and feels... numb. He seems less interested in me and towards everything in general. He often complains of having no energy, that he feels like sleeping all the time. I feel like he often forgets about me, does not answer my texts and ect. Normally I would not tolerate this behavior, but I don't know if it is because our relationship is going to end and he is losing interest or if he is genuinely getting worse from the pills (or despite the pills?) I tried talking to him several times, but he says 'it is what it is', but doesn't think the antidepressants would be a bad fit for him nor does he want to change them. If you have ever taken antidepressants: is this normal? How can I help?