Need other recipes with different lactose free milks, etc.
My boyfriend also can't have dairy, so I know this problem well! The problem is that non-dairy milks can't quite match the fat content of dairy milk.
You might try making frozen banana soft serve and mixing in the seeds of a vanilla bean:
I've had moderate success with using a blend of Silk soy milk and soy creamer to make the custard for ice cream. (The creamer has a higher fat content and mimics real cream.) The result will be a little bit icier than normal ice cream, but it's good.
Hemp milk is also higher in fat than other non dairy milks, but not everyone loves the taste. Let us know what you try!