My husbands card is ready for renewal .as we think his has got parkinson he can not sign the form

It all depends on what was in the contract you signed with him, or what was on the written quotation. If he just came and said, "it will cost you $10,500" and you paid him with no paperwork, you have no recourse. The only thing you can do is getting a building surveyor, and price the work and materials used, then use that against what you paid. Then go through small claims court. It is unlikely the builder will attend court, in which case you will win the case by default. The big problem is if you have no paperwork at all, just words.