Hmmmm what to do about a Husband that breaks the plumbing... Not sure I qualify to help with that...
On the other problem... these are simple pieces & parts. If it's part of the P-Trap which is where the leak is... head to Home Depot or Lowe's or your favorite Hardware store and purchase a new P-Trap. in fact there is a slight chance that he has simply cross threaded the part together... maybe disassemble it and try attaching it once again... see what happens. If that didn't help...
If its a Glued on piece of the plumbing... your going to need to decide if you can live with it or get it replaced. Living with it could be as simple as using " Rescue Tape" which is often sold at RV shows. Ken & Kathy ( forum name "KaKampers" ) are vendors for this very good product. Follow the instructions for the product and problem solved. Perhaps your DH solution will do fine... but then your here questioning his repair....
If you want the leaking pipe fitting replaced...look to see if there is enough pipe behind the pipe fitting that is leaking... that size of pipe needs 3/4 inch of pipe to slip inside the Hub part of the new fitting. Cut the old fitting off with a saw will do if there is only a short length of pipe left to work with... otherwise you might use a plastic pipe cutter. Make sure the cut is pretty square... clean the pipe before using "ABS" glue applied to both the cut pipe and the bell of the new fitting. REMEMBER when you put the new fitting in place it must be at the correct angle... the correct level, meaning plumb to the P-trap fitting that it must Mate too... if it's off by very much your going to have difficulty connecting the two thread parts together.
It's not as difficult as it sounds... just takes a little patience to get the job done.
Good Luck...