Is my SO jealous or?

So my sister thinks she's pregnant and she's in no situation where she should have a child! She got a part time job,lives at home and is only FWB with the guy. I'm a little upset too because me and my SO isn't ready either and he doesn't want kids for a few years and I've been having baby fever for a long while now. We talked about it and he says 'she's not fucking pregnant' 'she's screwed up' and 'Sure what's she gonna do if she is? Where is she gonna put the baby?' And we both talked about this and have said the same things. She was taking her BC recklessly and then stopped taking it without telling her FWB and now she's 7 days late.. All negative tests! I'm a little jealous by the fact she might be but I don't know if my SO seems jealous or what.. Opinions??