What do I do with my weird neighbor?

My neighbor is a middle aged guy. He is also obviously a little 'off' but not like a retard or anything. He has always bugged my family about stupid stuff. He used to ask us if we wanted to come over for pizza cause he wanted to order pizza hut. He did that every night for about 3 months until my husband told him we don't eat pizza hut because one of the workers had feces under their nails (my husband is a manager at PetSmart so people often respect his wisdom). Lately he has been getting a little pervy with my family and that is what is driving me nuts. I truly feel is unaware of his image he made himself. He found a pair of my daughter's underwear stuffed in a rabbit hole because she accidentally went number 2 in them while she was in the backyard (we have 2 acres). Ever since he keeps asking all of us if we can wash our daughter's underwear. He has been asking this every day for the last week and I am sick of it. He said he will 'scrub it clean in the sink and return it'. I dont even want my kids hearing that. My daughter already had a bad sexual run in with a very forceful prom date this past school year. The last thing she needs now is a crazy man going after her. What do I do? I dont want to get him in legal trouble but obviously I cant have this.