Parents second visit to US, Question regarding Sponsor

[MSASUD]

My parents have a Multiple entry Visitor Visa (B2) for 10 years (Issued in 2007).
I was on L1 Visa at that time and sponsored them. They visited in 2007 and were in US for around 3 months.

Now I'm on H4 (dependent) Visa. Can my parents still enter US on their visitor visa?

My husband is on H1 visa. If my parents have an invitation letter from my husband as the sponsor and his bank statements/pay slips, will it help at Port of entry to avoid complications? Is there any other document(s) required?

[immihelp]

1. Yes, they can.

2. Yes, that would help.