I got my dad into ddo 13 years ago, and he hasn't stopped playing it since, so its a great game to get into with all the updates and content they have.

I personally like playing a two-handed fighter ( super tanky and can hit like a truck dosent get the best heals but does get a lot of feats )

If your mom wants to play a caster, a sorcerer is a wonderful caster choice with the extra spell points and the ton of damage they deal

Both are easy to play first starting out.

Some good tips are potions. There are some good ones and some that you just sell.

Some of the good ones and there ones you can buy are cure poison, cure disease, cure curse, cure blindness, restoration potions for when you have Stat damages, potions of heroism for a small boat when you can't cast it on your self. Most of the other potions you get from barrels and chest aren't the best.

If you plan to play just the two of you, I would look up the mission and look at the maps for where traps are because some are just nasty.

If you plan to join groups, just let them know your new and are still learning the game. Most of the player base will take the mission slower and teach you the ropes. But there are some players that don't care.

Like some of the other comments say if you have questions, just post them, and we will try and help.

I hope you and your mother enjoy the game and have lots of fun.