At this very moment my DS 2.6 is sobbing because I am refusing to go into his cave (a blanket over a chair). It's one of his favorite games right now and I will play it with him at least a couple times a day, but not every time he asks. On the other hand DH does it whenever asked, DH really doesn't feel comfortable letting DS cry. DS is well used to both our styles. DH is more fun more of the time than I am, but we are both important to DS and I think my refusing to assist or play with him sometimes is helpful for him to develop some independence and ability to help or soothe himself. DS is used to my new style enough now (when he was a baby I picked him up or interacted with him immediately if he wanted it) that when I refuse something he cries, but only for a minute, and then moves right along to doing something else. I see him do all kinds of novel and imaginative things while entertaining himself that he doesn't do with DH.
Having said that, that there can be something good to come out of being ignored, it obviously would be a poor parent who ignored their child all the time or any time when the child truly needed assistance (stuck, very hungry, etc). If that's the case then maybe your DH isn't around the child enough to feel connected with them, or enough to understand his current needs (he may still be stuck thinking the child is a couple months younger, easy to happen if dad is not around a lot). So either more time with him or maybe some detailed suggestions for activities to do with him could be useful.
Polly