sab> it's not unusual for guys not to know their exact reservist arrangements until much later cos the training programme etc may take some time to be finalised. i do think, however, that you can call up the unit and just ask (yes, YOU, as the wife)
actually, given that your baby will be very very young in october, it might be possible for your husband to defer his reservist. you might wanna ask him to check it out. i know they allow deferment on compassionate grounds for wife's delivery etc. refer below:
Q13. What is deferment and how can I defer from my scheduled NS training?
NSmen are required to report for Operationally Ready National Service (ORNS) training, as scheduled by their NS Unit. However, under certain circumstances, deferment from National Service may be granted. Deferment from NS allows NSman to postpone his NS call-up to a later date within the same workyear (1st April of the current year to 31st March of the following year), and may be considered under exceptional circumstances such as
a. On compassionate grounds, for example marriage & honeymoon, wife's delivery, next-of-kin is seriously ill, etc
b. National Representation at recognised regional and International games
c. New employment
d. Newly established business
e. Examination for part-time studies
f. Simultaneous call-up of 2 or more NSmen within the same department and who are employed in the same job capacity.
NSmen should submit their deferment application to NSSC before the commencement of the ICT with the following details
a. Rank & Name / NRIC,
b. Unit Duration and type of ICT (i.e. Upgrading course, BCTC)
c. Reasons for deferment application (with supporting documents) and Contact details.
NSmen may be deferred if their reasons for applications are within MINDEF guidelines.
a. Applications, which meet guidelines, will usually be informed of the decision within 14 working days.
b. An appeal against a rejected deferment application should be submitted for re-consideration.
c. Where the unit CO does not support the appeal for deferment, the appeal will be submitted to the higher HQ for review, thereby ensuring that a higher authority is considering the appeal.
d. NSman who is granted deferment will have to undergo make-up training for the deferred period within the same work year.
MINDEF does not encourage deferment as it affects the unit's operational requirements.
(The above is from ns.sg)
Regarding staying in, it's quite unusual for reservist personnel to have to stay in (cos camps seldom have the extra bunk space unless special arrangements have been made) but if there are overnight exercises, he can't come home not cos he has to stay in camp but cos he's outfield during the exercise...