Primary H1B in india for H1B visa stamping - Spouse on H4 EAD in USA



Primary H1B wants to travel India for a month.Need to go for H1B visa stamping.

Spouse on H4 EAD in USA.

Question: If H1B gets 221g, Can spouse on H4 EAD stay in USA untill H1B 221g gets resolved?

How long can spouse H4 EAD stay in USA, when the primary H1B in India.