While it is possible to sleep train, I would say don’t bother since baby is only 2.5mo. You can be sleep training and then all it takes is one tooth to disrupt the entire routine 😅. I personally don’t sleep train my baby, she just find her own routine and stick to it. Any growth spurts or teething phase will throw the entire routine off. She started sleeping thru the night at 8mo. I will just let her roll and cry herself while I lay beside her. She will self soothe and sleep.
You can try observing his sleep pattern for the first 2.5months. When did he start to sleep a long stretch of hours then slowly move the timing forward. If he used to be sleeping at 12 midnight and suddenly you want him to sleep at 7pm, he will definitely be fussy and not wanting to sleep. Setting up a consistent bedtime routine helps too.