Boooo! Live life in the fast lane.
Not everyone wants to pay lawyers to write their letters, terms, contracts etc etc and if your client is still keen for you to do it after you've advised them to get legal advice then go for it.
Depending on size of the client and the services they’re offering, it doesn't have to be difficult - or dangerous - to write your own.
Use templates, look at what similar sites have etc - collect it all together and make something from that. Check it with someone qualified if you're worried.
And in your contract, any liability for the documents provided you sign off to the client. Done.