Can anyone tell me about IRS forms 1023 and 990 for 5031c board. Can a husband and wife serve on same board?

I think you mean 501(c)(3) board, correct?

Yes, a husband and wife can serve on the same not-for-profit board of directors, as long as it doesn't violate the organization's bylaws. I would argue that it's probably not a good idea to have two spouses on the board at the same time, but the IRS doesn't have a rule against it.