You are entitled to the homemakers allowance
You are also entitled to increase your credits by your wifes credits excl the PAYE credit. In addition depending on how your SRCOP is split you may be entitled to an additional 9,000. This effectively means you can earn an additional 9,000 at the lower rate of tax assuming you are currently paying tax at the higher rate.
Well, if she is incapable of work, she can claim Illness Benefit, if capable and available; Jobseeker's Benefit. The 'Homemaker's Allowance' mentioned by previuous poster is possibly the 'Homemaker's Scheme' which gives her credits or disregards years for pension purposes. Ther is no allowance payable.