Family with 4 young children can stay in one room?
G Kelawei is more to a business hotel... Try G Gurney which is beside G Kelawei... It's meant for holiday goers and family.
Suggest you contact the hotel by phone/email (they are very friendly), as the room we stayed in recently had an adjacent room (that we hadn't booked). Each room had it's own security door, that could be kept open if desired, as both rooms were able to be contained within a SINGLE security door to the main corridor, ie. effectively producing a 2 bed-room suite. They could also advise whether their slightly larger sister hotel G Hotel Gurney next door (same general management) had other options for you.
Get an answer from G Hotel Kelawai staff and past guests.