Indoor photos can be done using a flash, and learning how to use one, or with existing light, and learning how to do that. I've done sports and events where flash has usually not been an option. The advantage to using existing light can sometimes be getting photos of more natural interactions with subjects doing whatever they're doing and not noticing you and your camera; a flash usually can make people aware of the camera.
Shooting something indoors I often may try for a sunny day, open blinds, turn on plenty of lights, and I've even angled lamp shades to get more light onto the subject.
These actually I think with some cropping could be nice photos. There's more background than you need but these look like you were on the floor playing with him and he was into what he was doing. I like him and the dinosaur! crop down that background and you'd have some real keepers I think. I also really like these in B&W.