What do you mean by groom them? We dont' do anything but clip the nails and I haven't been doing that because I am always afraid I will hurt her. I was having a local dog groomer clip the nails for me. You should be able to take him to a vet to have the nails trimmed. You can have the wings trimmed so if he gets out he can't fly. This is a good thing to do until you have gotten him tamed.
If that doesn't work do you have a breeder in driving distance that would do it for you or a pet store that might do it for a fee.
The best way to relate to him is with a calm voice and babyish talk. if you are scared you are going to tense him up too. He is essentially a wild animal.
I never push my birds any farther than they want to go. It takes a lot of patience and time to build a relationship with him. It isn't a matter of training like you would a dog. They are smart! You just need to learn to speak Bird! and I don't mean tweet tweet! LOL
There are some great bird sites that deal with suggestions on this.
My favorite one is Cockatiel Cottage. They have an excellent site with lots of good advice and ideas.
http://cockatielcottage.net/bite.html
About toys---there are lots of things you can make. I take a toilet paper roll and cut it about 1/4" wide into a curlique and then I poke a hole in the center of crackers and carefully thread the cardboard through the hole. The crackers are easier to create the hole if you use a knife and just punch out the center with the tip of the knife. If you do it gently the cracker won't break. I thread about 4 onto a long strip and spread them out. It gives the bird something to chew on that won't hurt him and the crackers give him something to figure out. They love to drop the crackers so they will work and work to get it off of the cardboard strip.
Look up homemade bird toys and you will find alot of differant good ideas. I found a rawhide shoe that was a dog treat and I hung it in the corner of her cage. She is so funny she gets up under it and hits it with her beak and beats at it and she gets it to spinning. I call it her work out! She can have that thing spinning so hard you wonder how it stays on! I also have a toy I bought that is 4 toothbrushes and some plastic rings. She works and works to pull a toothbrush over the top of her perch.
This cockatiel is the first one I have ever had that can talk. She picked up on my calling her a pretty girl and when she sees me she hollers Pretty Girl Pretty Girl to get my attention. She relates that phrase to me. DH she uses Good Girl. That is the extent of her talking but it is fun to hear. She won't do it very often when anyone else is here.
I'm sure there are lots more I can think of to pass on.