Mi husband got operated for hernia with leproscopy under ga. After that his BP is low. Maintaned only with medicines in icu. Will it stabilise? ..

Should be fine. While there is not enough info here to say for sure, postoperative low BP is fairly common, and usuay self limited. There are many factors involved that play in to the severity and prognosis of the problem, but in planned/elective surgical procedures, it is very rare for this to be an unresolvable problem.
Depends. Depends on many factors: cardiac function, blood loss, coexisting diseases, unintentional complications during surgery, base line condition, etc. Talk to ICU physician.
It depends on. Why his pressure is low. The ICU docs should give you an idea what the core problem is and how they hope for things to progress. This is an unual outcome and, i suspect that the story is more complicated than you were able to state in this forum. Good luck.